Junk & Jonathan: Part 6—Chapter 3

This is part 6 of my review of The Myth of Junk DNA. For a list of other postings on this topic see the link to Genomes & Junk DNA in the "theme box" below or in the sidebar under "Themes."

We learn in Chapter 9 that Wells has two categories of evidence against junk DNA. The first covers evidence that sequences probably have a function and the second covers specific known examples of functional sequences. In the first category there are two lines of evidence: transcription and conservation. Both of them are covered in Chapter 3 making this one of the most important chapters in the book. The remaining category of specific examples is described in Chapters 4-7.

The title of Chapter 3 is Most DNA Is Transcribed into RNA. As you might have anticipated, the focus of Wells' discussion is the ENCODE pilot project that detected abundant transcription in the 1% of the genome that they analyzed (ENCODE Project Consortium, 2007). Their results suggest that most of the genome is transcribed. Other studies support this idea and show that transcripts often overlap and many of them come from the opposite strand in a gene giving rise to antisense RNAs.

The original Nature paper says,

... our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another.

The authors of these studies firmly believe that evidence of transcription is evidence of function. This has even led some of them to propose a new definition of a gene [see What is a gene, post-ENCODE?]. There's no doubt that many molecular biologists take this data to mean that most of our genome has a function and that's the same point that Wells makes in his book. It's evidence against junk DNA.

What are these transcripts doing? Wells devotes a section to "Specific Functions of Non-Protein-Coding RNAs." These RNAs may be news to most readers but they are well known to biochemists and molecular biologists. This is not the place to describe all the known functional non-coding RNAs but keep in mind that there are three main categories: ribosomal RNA (rRNA), transfer RNA (tRNA), and a heterogeneous category called small RNAs. There are dozens of different kinds of small RNAs including unique ones such as the 7SL RNA of signal recognition factor, the P1 RNA of RNAse P and the guide RNA in telomerase. Other categories include the spliceosome RNAs, snoRNAs, piRNAs, siRNAs, and miRNAs. These RNAs have been studied for decades. It's important to note that the confirmed examples are transcribed from genes that make up less than 1% of the genome.

One interesting category is called "long noncoding RNAs" or lncRNAs. As the name implies, these RNAs are longer that the typical small RNAs. Their functions, if any, are largely unknown although a few have been characterized. If we add up all the genes for these RNAs and assume they are functional it will account for about 0.1% of the genome so this isn't an important category in the discussion about junk DNA.

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& Junk DNASo, we're left with a puzzle. If more than 90% of the genome is transcribed but we only know about a small number of functional RNAs then what about the rest?

Opponents of junk DNA—both creationists and scientists—would have you believe that there's a lot we don't know about genomes and RNA. They believe that we will eventually find functions for all this RNA and prove that the DNA that produces them isn't junk. This is a genuine scientific controversy. What do their scientific opponents (I am one) say about the ENCODE result?

Criticisms of the ENCODE analysis take two forms ...

• The data is wrong and only a small fraction of the genome is transcribed
• The data is mostly correct but the transcription is spurious and accidental. Most of the products are junk RNA.

Criticisms of the Data

Several papers have appeared that call into question the techniques used by the ENCODE consortium. They claim that many of the identified transcribed regions are artifacts. This is especially true of the repetitive regions of the genome that make up more than half of the total content. If any one of these regions is transcribed then the transcript will likely hybridize to the remaining repeats giving a false impression of the amount of DNA that is actually transcribed.

Of course, Wells doesn't mention any of these criticisms in Chapter 3. In fact, he implies that every published paper is completely accurate in spite of the fact that most of them have never been replicated and many have been challenged by subsequent work. The readers of The Myth of Junk DNA will assume, intentionally or otherwise, that if a paper appears in the scientific literature it must be true.

But criticism of the ENCODE results are so widespread that they can't be ignored so Wells is forced to deal with them in Chapter 8. (Why not in Chapter 3 when they are first mentioned?) In particular, Wells has to address the van Bakel et al. (2010) paper from Tim Hughes' lab here in Toronto. This paper was widely discussed when it came out last year [see: Junk RNA or Imaginary RNA?]. We'll deal with it when I cover Chapter 9 but, suffice to say, Wells dismisses the criticism.

Criticisms of the Interpretation

The other form of criticism focuses on the interpretation of the data rather than its accuracy. Most of us who teach transcription take pains to point out to our students that RNA polymerase binds non-specifically to DNA and that much of this binding will result in spurious transcription at a very low frequency. This is exactly what we expect from a knowledge of transcription initiation [How RNA Polymerase Binds to DNA]. The ENCODE data shows that most of the genome is "transcribed" at a frequency of once every few generations (or days) and this is exactly what we expect from spurious transcription. The RNAs are non-functional accidents due to the sloppiness of the process [Useful RNAs?].

Wells doesn't mention any of this. I don't know if that's because he's ignorant of the basic biochemistry and hasn't read the papers or whether he is deliberately trying to mislead his readers. It's probably a bit of both.

It's not as if this is some secret known only to the experts. The possibility of spurious transcription has come up frequently in the scientific literature in the past few years. For example, Guttmann et al. (2009) write,

Genomic projects over the past decade have used shotgun sequencing and microarray hybridization to obtain evidence for many thousands of additional non-coding transcripts in mammals. Although the number of transcripts has grown, so too have the doubts as to whether most are biologically functional. The main concern was raised by the observation that most of the intergenic transcripts show little to no evolutionary conservation. Strictly speaking, the absence of evolutionary conservation cannot prove the absence of function. But the remarkably low rate of conservation seen in the current catalogues of large non-coding transcripts (less than 5% of cases) is unprecedented and would require that each mammalian clade evolves its own distinct repertoire of non-coding transcripts. Instead, the data suggest that the current catalogues may consist largely of transcriptional noise, with a minority of bona fide functional lincRNAs hidden amid this background.

This paper is in the Wells reference list so we know that he has read it.

What these authors are saying is that the data is consistent with spurious transcription (noise). Part of the evidence is the lack of any sequence conservation among the transcripts. It's as though they were mostly derived from junk DNA.

Sequence Conservation

Recall that the purpose of Chapter 3 is to show that junk DNA is probably functional. The first part of the chapter reportedly shows that most of our genome is transcribed. The second part addresses sequence conservation.

Here's what Wells says about sequence conservation.

Widespread transcription of non-protein-coding DNA suggests that the RNAs produced from such DNA might serve biological functions. Ironically, the suggestion that much non-protein-coding DNA might be functional also comes from evolutionary theory. If two lineages diverge from a common ancestor that possesses regions of non-protein-coding DNA, and these regions are really nonfunctional, then they will accumulate random mutations that are not weeded out by natural selection. Many generations later, the sequences of the corresponding non-protein-coding regions in the two descendant lineages will probably be very different. [Due to fixation by random genetic drift—LAM] On the other hand, if the original non-protein-coding DNA was functional, then natural selection will tend to weed out mutations affecting that function. Many generations later, the sequences of the corresponding non-protein-coding regions in the two descendant lineages will still be similar. (In evolutionary terminology, the sequences will be "conserved.") Turning the logic around, Darwinian theory implies that if evolutionarily divergent organisms share similar non-protein-coding DNA sequences, those sequences are probably functional.

Wells then references a few papers that have detected such conserved sequences, including the Guttmann et al. (2009) paper mentioned above. They found "over a thousand highly conserved large non-coding RNAs in mammals." Indeed they did, and this is strong evidence of function.¹ Every biochemist and molecular biologist will agree. One thousand lncRNAs represent 0.08% of the genome. The sum total of all other conserved sequences is also less than 1%. Wells forgets to mention this in his book. He also forgets to mention the other point that Guttman et al. make; namely, that the lack of sequence conservation suggests that the vast majority of transcripts are non-functional. (Oops!)

There's irony here. We know that the sequences of junk DNA are not conserved and this is taken as evidence (not conclusive) that the DNA is non-functional. The genetic load argument makes the same point. We know that the vast majority of spurious RNA transcripts are also not conserved from species to species and this strongly suggests that those RNAs are not functional. Wells ignores this point entirely—it never comes up anywhere in his book. On the other hand, when a small percentage of DNA (and transcripts) are conserved, this gets prominent mention.

Wells doesn't believe in common ancestry so he doesn't believe that sequences are "conserved." (Presumably they reflect common design or something like that.) Nevertheless, when an evolutionary argument of conservation suits his purpose he's happy to invoke it, while, at the same time, ignoring the far more important argument about lack of conservation of the vast majority of spurious transcripts. Isn't that strange behavior?

The bottom line hear is that Jonathan Wells is correct to point to the ENCODE data as a problem for junk DNA proponents. This is part of the ongoing scientific controversy over the amount of junk in our genome. Where I fault Wells is his failure to explain to his readers that this is disputed data and interpretation. There's no slam-dunk case for function here. In fact, the tide seems to turning more and more against the original interpretation of the data. Most knowledgeable biochemists and molecular biologists do not believe that >90% of our genome is transcribed to produce functional RNAs.

UPDATE: How much of the genome do we expect to be transcribed on a regular basis? Protein-encoding genes account for about 30% of the genome, including introns (mostly junk). They will be transcribed. Other genes produce functional RNAs and together they cover about 3% of the genome. Thus, we expect that roughly a third of the genome will be transcribed at some time during development. We also expect that a lot more of the genome will be transcribed on rare occasions just because of spurious (accidental) transcription initiation. This doesn't count. Some pseudogenes, defective transposons, and endogenous retroviruses have retained the ability to be transcribed on a regular basis. This may account for another 1-2% of the genome. They produce junk RNA.

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1. Conservation is not proof of function. In an effort to test this hypothesis Nöbrega et al. (2004) deleted two large regions of the mouse genome containing large numbers of sequences corresponding to conserved non-coding RNAs. They found that the mice with the deleted regions showed no phenotypic effects indicating that the DNA was junk. Jonathan Wells forgot to mention this experiment in his book.

Guttman, M. et al. (2009) Chromatin signature reveals over a thousand highly conserved non-coding RNAs in mammals. Nature 458:223-227. [NIH Public Access]

Nörega, M.A., Zhu, Y., Plajzer-Frick, I., Afzal, V. and Rubin, E.M. (2004) Megabase deletions of gene deserts result in viable mice. Nature 431:988-993. [Nature]

The ENCODE Project Consortium (2007) Nature 447:799-816. [PDF]

A Poll: How Much of the Human Genome Is Junk?

It's time for another poll. Please answer the question in the sidebar.

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Junk & Jonathan: Part 5—Chapter 2

This is part of my review of The Myth of Junk DNA. For a list of other postings on this topic see the link to Genomes & Junk DNA in the "theme box" below or in the sidebar under "Themes."

Chapter 2 is Junk DNA: The Last Icon of Evolution? It's mostly an explanation of how the concept of junk DNA fits into evolution. According to Wells, Darwin's theory of evolution by natural selection explains how living things descend with modification from a common ancestor. (Recall that Wells rejects common ancestry.) Wells explains that Darwin's original idea has been extended with the discovery of DNA. He describes "neo-Darwinism" like this ...

According to neo-Darwinism, traits are passed on by genes that reside on microscopic thread-like structures in the cells called chromosomes, and new traits arise from accidental genetic mutations.

In order to clear up any confusion, Wells tells us that, "... I will use "Darwinism" in the rest of the book to mean both Darwin's theory and neo-Darwinism" (p. 19). This is important since it's clear that he's talking about the theory of natural selection when he talks about Darwinism or neo-Darwinism.

Wells describes how Ohno coined the term "junk" DNA in 1972 then quotes Richard Dawkins as a supporter of junk. He states his belief that a couple of papers on selfish DNA in 1980 were taken as evidence of junk. He concludes that ...

... some biologists were skeptical of the notion of "junk DNA" from the very beginning—though most accepted it.

Wells fails to distinguish between those biologists who recognize the existence of junk DNA (e.g. pseudogenes) and those who thought that most of our genome is junk. I still believe that only a minority of biologists think that most our genome is junk. I also think that many biologists make a distinction between "junk" and "selfish." I know I do. In my mind "selfish" DNA, such as active transposons or endogenous retroviruses, isn't junk.

Next comes a couple of pages under the subheading "Using Junk DNA as Evidence for Darwinism and Against Intelligent Design." The usual suspects are mentioned. He quotes Ken Miller, Douglas Futuyma, Michael Shermer, Francis Collins, Phil Kitcher, Jerry Coyne, and John Avise. Although their emphasis varies, they all make the point that the presence of junk DNA in our genome is not consistent with intelligent design. It is, however, consistent with evolution (but not natural selection).

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& Junk DNAIt's important to note that biologists don't, with rare exceptions, claim that the presence of junk DNA is evidence for Darwinism or evolution. It's consistent with our understanding of modern evolutionary theory but compact genomes with no junk would also be consistent with evolution, especially evolution by natural selection.

Most of these writers are pointing out how difficult it is for Intelligent Design Creationists to make their case in light of massive amounts of junk in our genome. They are mostly arguing against design and not for evolution.¹ This point will come up again in Chapter 10.

Wells concludes with ...

The arguments by Dawkins, Miller, Shermer, Collins, Kitcher, Coyne and Avise rest on the assumption that most non-coding DNA is junk, without any significant biological function. Yet a virtual flood of recent evidence shows that they are mistaken: Much of the DNA they claim to be "junk" actually performs important functions in living cells.

The stage is set. In the rest of the book, Jonathan Wells will try and convince us that most of the DNA in our genome is not junk. Pay attention 'cause it's important to keep the main focus of the dispute in center stage. What the scientists are saying is that there's a lot of junk in our genome and, in order to blunt that attack on design, Wells has to show that there's not very much junk DNA (perhaps none). It won't be sufficient to show that a few percent here and there aren't junk. Any amount of junk DNA is a threat to the basic concept of intelligent design. That's why the IDiots are so worried.

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1. I often make the same argument against adaptationists. Some of them see design by natural selection as the dominant feature of evolution but that's not what our genome tells us. There's no illusion of apparent design in our genome sequence.

Junk & Jonathan: Part 4—Chapter 1

I received a copy of the book a few days ago and this is my first posting on its contents. For a list of other postings on this topic see the link to Genomes & Junk DNA in the "theme box" below or in the sidebar under "Themes."

This is a very small book. There's only 114 pages of text—it's more like a large pamphlet than a book. If I'd read it from front to back in one sitting it would only have taken an hour or so. But I couldn't read it in one go because nobody can put up with IDiot rhetoric for that long!

Chapter 1 is The Controversy over Darwinian Evolution. It has nothing to do with junk DNA.

Wells begins by telling his readers that evolution is a fact. By that he means "microevolution." Wells doesn't believe in macroevolution or common descent and he even challenges the evidence for speciation. As usual, he supports his claims with selected quotations from scientists.

Sixty year after Dobzansky wrote this, biologists had still not observed the origin of a new species ("speciation") by natural selection. In 1997, evolutionary biologist Keith Stewart Thomson wrote: "A matter of unfinished business for biologists is the identification of evolution's smoking gun," and "the smoking gun of evolution is speciation, not local adaptation and differentiation of populations."

Wells is telling his readers that as long as biologists have not directly observed a new species forming then speciation has not been demonstrated. This rules out all evidence from the fossil record and all evidence from molecular phylogeny. Nice trick.

Problem is, there's lots of lots of evidence for speciation, including some examples where speciation has been caught in the act. Wells, like most IDiots, doesn't understand how evolution works. He seems to think that new species will form overnight and that all biologist have to do is keep their eyes open and record the examples.

I don't know for sure whether Wells intends to emphasize speciation by natural selection when he claims that, "biologists had still not observed the origin of a new species ("speciation") by natural selection." If that's his intent then it's true that there are very few examples of true speciation (biological species concept) that can be attributed directly to natural selection. As Jerry Coyne points out, reproductive isolation is mostly due to accident (random genetic drift) and not natural selection [The Cause of Speciation]. That's in line with modern evolutionary theory and Coyne should know because he's one of the world's leading experts on speciation. [UPDATE: Coyne and some commenters have corrected me. Coyne actually does think that most speciation is due to natural selection. I'll stick with Futuyma as my authority. He's much more open to the idea of speciation by random genetic drift (Evolution 2nd ed. p. 447)]

There are two possibilities here. Either Wells is deliberately misleading his readers by emphasizing that speciation must occur by natural selection or he's ignorant of modern evolutionary theory. Since most IDiots have a concept of evolution that dates back to the nineteenth century, I'll go with the second explanation. However, there's almost certainly an element of deception in his remarks since Jonathan Wells has a long history of deliberately misrepresenting evolution.

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& Junk DNASo, Wells is dead wrong about the first point in his book. There's abundant evidence of speciation (and macroevolution) and, furthermore, modern evolutionary theory does not attribute speciation exclusively to adaptation (i.e. there's more to evolution than Darwinism).

The importance of Wells' rejection of macroevolution will become obvious later on in the book when he argues that Intelligent Design Creationism does not rule out common ancestry. He agrees that someone like Michael Behe can believe in common descent and still be a card-carrying IDiot.

By the way, Wells is clever enough to cover his bases in case speciation is ever observed.

Of course, even if scientists eventually observe the origin of a new species by natural selection, the observation would not mean that natural selection can also explain the origin of significantly new organs or body plans. But the fact that scientists have not observed even the first step in macroevolution means that "evolution's smoking gun" is still missing.

The rest of the chapter (three pages) is a re-hash of arguments Wells made in Icons of Evolution and elsewhere.

• The Cambrian Explosion "contradicts Darwin's theory that major differences should arise only after millions of years of evolution ...."
• Molecular evolution isn't accurate: "molecular evidence is plagued with inconsistencies." The rejection of molecular evidence as unreliable is going to cause problems for Wells later on since he relies on it for some of his arguments about junk DNA. As usual, the IDiots want to have their cake and eat it too.
• Homology is a circular argument, according to Wells, so you can't use homology as evidence for evolution. That's correct. Similarity is the evidence and homology is the conclusion. This flaw in Wells' reasoning has been pointed out to him repeatedly over the past decade but he ignores all criticism and continues to use arguments that have been refuted.
• The Haeckel drawings were fakes and, "The truth is that vertebrate embryos start out looking very different from each other, then they converge somewhat in appearance midway through development before diverging as they mature." This has nothing to do with junk DNA so I won't discuss the massive amount of embryological evidence for evolution.

Wells closes with,

So microevolution is a fact, supported by overwhelming evidence, but macroevolution remains an assumption, illustrated with icons that misrepresent the evidence or rely on circular reasoning. The icons are not science, but myth.

This sets the tone for the rest of the book. Even though it is filled with references to the scientific literature there's never any discussion of alternative hypotheses or conflicting data. This is not a book where the author wants to inform his readers about the exciting controversies and conflicts within science. This is a book where the author wants to promote creationism by attacking and misrepresenting evolution using faulty logic and untruths.

The next paragraph is quite interesting. He invokes the beliefs of Americans as support for his claims. Apparently they're much more perceptive that the typical evolutionary biologist. (I wonder what he thinks of Australians and Europeans?)

This may be one reason why—despite the Darwinists' near-monopoly over science education—most Americans still reject the doctrine that human beings evolved from ape-like ancestors by unguided processes such as random variation and survival of the fittest.

I think this means that Wells also rejects common ancestry. If so, it will mean that he can't use it to support any of his arguments later on in the book, right?

Finally, at the very end of the chapter we get to the point,

In the 1950s, neo-Darwinists equated genes with DNA sequences and assumed that their biological significance lay in the proteins the encoded. But when molecular biologists discovered in the 1970s that most of our DNA does not code for proteins, neo-Darwinists called non-protein-coding DNA "junk" and attributed it to molecular accidents that have accumulated in the course of evolution. Like peppered moths, Galapagos finches, Darwin's Tree of Life, homology in vertebrate limbs, and Haeckel's embryos, "junk DNA" has become an icon of evolution. But is it science of myth?

I've discussed Wells' ignorance of history in previous postings but, for the record, here are the facts.

• By the 1970s molecular biologist were well aware of the fact that non-protein coding genes existed (e.g. ribosomal RNA genes, tRNA genes etc.)
• By the 1970s molecular biologists knew of several functions of DNA sequences that weren't genes. Origins of replication and regulatory sequences were well-known but there were others.
• Even in the 1970s no knowledgeable molecular biologist could ever defend the idea that all non-coding DNA was junk. (It's true that there were some stupid scientists who weren't aware of tRNA genes and regulatory sequences and made silly statement because of their ignorance but they don't count.)
• By the 1970s junk DNA was a fact. The scientific controversy was over how much of our genome is junk. Is it the majority or only a small percentage?
• By the 1970s knowledgeable evolutionary biologists were well aware of the fact that most of our genome was mutating and evolving as though most changes were neutral (genetic load arguments). This didn't mean that most of our genome was junk but it did mean that the sequence couldn't be important or we would never be able to tolerate the genetic load. This was not common knowledge among biologists—still isn't.
• By the 1970s most molecular biologists were aware of the so-called "C-value paradox" where very closely related species have very different genome sizes. They correctly interpreted this to mean that the species with the large genomes probably didn't need all that extra DNA. (Up until now, Intelligent Design Creationists have not offered a reasonable answer to The Onion Test. Wells tries on Chapter 8.)
• The proponents of large amounts of junk DNA in our genome would hardly ever have referred to themselves as "Darwinist" or "neo-Darwinists." In fact, they tended to be among those evolutionary biologists who opposed adaptationism and favored Neutral Theory and random genetic drift. Pluralist concepts were much more compatible with the idea of significant amounts of junk DNA than strict "Darwinist" interpretations of genome evolution.

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See the IDiots Gloat over Jonathan Wells

This is part of my discussion about The Myth of Junk DNA by Jonathan Wells. I still haven't read the book—it won't be released in Canada until May 31st.

Over on Evolution News & Views (sic) David Klinghoffer is already counting his chickens [Junk DNA and the Darwinist Response so Far].

Over the weekend, Jonathan Wells's The Myth of Junk DNA broke into the top five on Amazon's list of books dealing with genetics -- a list normally dominated at its pinnacle by various editions of Richard Dawkins' The Selfish Gene. Not bad, Jonathan.

Not bad indeed, except I can't tell if it's true. When I check the top selling recently published books I don't see The Myth of Junk DNA in the top five. Never mind, I'm sure there will be many skeptics like me who will buy the book just for a good laugh.

UPDATE: The latest information shows that Wells' book is ranked 23rd under "Genetics." I'm sure the IDiots just made a simple arithmetic error when they said it had broken into the top five.

The juxtaposition with Dawkins' Selfish Gene is appropriate, notwithstanding the demurrals of biochemist Larry Moran et al. Dawkins and other Darwinists, such as Jerry Coyne, have indeed posited that neo-Darwinian theory predicts that swaths of the genome will turn out to be functionless junk. The Junk DNA argument has been a pillar of the Darwin Lobby's efforts to seduce public opinion and influence public policy. Professor Moran wants to imagine that Dawkins never held that neo-Darwinism predicts junk DNA. But that's not how other Darwinists see it. (Compare, for example, Dennett's Darwin's Dangerous Idea, page 316.)

The IDiots have a bit of a problem. In order to make this book look important they have to first establish that the concept of abundant junk DNA in our genome was a "pillar" of support for evolution. That's hard to do when their understanding of evolution is so flawed that they don't see the difference between "Darwinism" and evolution by random genetic drift.

Their claim that evolutionary theory PREDICTED the presence of huge amounts of junk DNA in our genome is just plain false. They been told this but they keep repeating their error. There's a word for that kind of behavior.

It's easy to see how they got confused. It's because they're IDiots. It's partly because they don't understand that an argument for inheritance of a few pseudogenes is not the same as an argument that more than 50% of our genome is junk. There are plenty of scientists who will use the pseudogene argument to challenge Intelligent Design Creationism but who don't believe that MOST of our genome is junk.

It's also partly because the IDiots don't know the difference between selfish DNA and junk. Here's what Daniel Dennett says on page 316 of Darwin's Dangerous Idea.

The presence of functionless DNA in the genome is no longer regarded as a puzzle. Dawkins (1976) selfish-gene theory predicts it, and elaborations on the idea of "selfish DNA" were simultaneously developed by Doolittle and Sapeinza (1980) and Orgel and Crick (1980) (see Dawkins 1982, ch. 9, for the details).

Selfish DNA is not junk DNA. The classic examples of selfish DNA are active transposons and integrated viruses. These bits of DNA have a function—even if it's only to propagate themselves. As you can see from my summary [What's in Your Genome?]. I don't count them as junk.

It's remarkable that Klinghoffer quotes Chapter 9 of The Extended Phenotype (1982) since Dawkins take pains to point out that much of the junk DNA in our genome could have a function. This is exactly the sort of skepticism one would expect from a Darwinist.

This does not mean, however, that the so-called junk DNA is not subject to natural selection. Various 'functions' for it have been proposed, where 'function' means adaptive benefit to the organism.

He goes on to describe several of the proposals that are common arguments against junk DNA. If the DNA has a function and it's adaptive, then it is not junk. Selfish DNA is not junk.

Let's be very clear about one thing. The scientific dispute is not over the existence of junk DNA. That's well established. The dispute is over how much of our genome is junk (DNA with no function). In order to refute the idea that MOST of our genome is junk, you have to show that most of it has a function of some sort. I'm looking forward to Jonathan Wells' book where he is going to prove to us that >50% of our genome has a function. (Not holding my breath!)

So far, with none of them having actually read the book (though P.Z. Myers threatens to do so), the Darwin apologists' response to The Myth of Junk DNA has followed along four lines of defense.

1) The usual insults. In his blog Larry Moran of the Department of Biochemistry at the University of Toronto, a grown man and from the looks of him not a young one either, repetitively derides Jonathan as an "IDiot." (How embarrassing for this mature gentleman, you might think. Can you imagine Jonathan Wells or anyone else prominent in the ID community replying in kind, designating Professor Moran as "Larry Moron" or similar? The question is self-answering and tells you a lot about how desperation kindles anger among these people.)

You know, there's one sure way to prove you're not an idiot. The IDiots have been trying for over twenty years to show that they understand science. I'll gladly stop calling them idiots as soon as they deserve it.

Speaking of insults. There's one sure way to ensure that you aren't going to be insulted and that's to stop calling evolutionary biologists "Darwinists" and stop saying that they don't understand their own discipline. I find that extremely insulting and I'm not going to refrain from responding in kind.

I don't know what Jonathan Wells is going to say in his latest book but here's a few examples of insults in Icons of Evolution.

There is a pattern here, and it demands an explanation. Instead of continually testing their theory against the evidence, as scientists are supposed to do, some Darwinists consistently ignore, explain away, or misrepresent the biological facts in order to promote their theory. One isolate example of such behavior might be due simply to overzealousness. Maybe even two. But ten? Year after year? (p. 230)

Fraud is a dirty word, and it should not be used lightly. In the cases described in this book, dogmatic promoters of Darwinism did not see themselves as deceivers. Yet they seriously distorted the evidence—often knowingly. If this is fraud when a stock promoter does it, what is it when a scientist does it? (p. 234)

If dogmatic promoters of Darwinian evolution were merely distorting the truth, that would be bad enough. But they haven't stopped there. They now dominate the biological sciences in the English-speaking world, and use their position of dominance to censor dissenting viewpoints. (p. 235)

The truth is that a surprising number of biologists quietly doubt or reject some of the grander claims of Darwinian evolution. But—at least in America—the must keep their mouths shut or risk condemnation, marginalization, and eventual expulsion from the scientific community. This happens infrequently, but often enough to remind everyone that the risk is real. (p. 239)

Klinghoffer continues with his four lines of defense that we "Darwinists" apparently use to defend the existence of abundant junk DNA (>50%) in our genome.

2) Denying that junk DNA ever figured preeminently in the Darwinist's quiver of arguments against design. Moran, for example, asserts, "There was never a time when knowledgeable molecular biologists equated 'junk' DNA and 'noncoding' DNA." Huh, that's strange. I'm not aware of anyone who has scientifically polled the community of professional biologists on the subject. But I do know that in the struggle for public opinion over the question of Darwin versus Design, junk DNA has again and again been employed, by all the most eminent protagonists on the Darwinian side, as a bludgeoning weapon against intelligent design. Never mind The Selfish Gene, in his most recent book, The Greatest Show on Earth (2009), Dawkins observed that "the greater part...of the genome might as well not be there, for all the difference it makes," and that this fact is "useful for...embarrassing creationists."

Similarly, in Why Evolution Is True (2009), Jerry Coyne offers it, again, as a "prediction" of neo-Darwinian theory that we'll find the genome littered with useless "vestigial genes."

I said that knowledgeable scientists never said that all non-coding DNA is junk. Klinghoffer says, blah, blah, blah, not even addressing my statement.

You can't make this stuff up. At every single opportunity the IDiots demonstrate that they deserve the title.

3) When not denying that junk DNA is a prime, staple argument for Darwin apologists, Professor Moran wants to have it the opposite way. In the same series of blog posts attacking "the IDiot" Jonathan Wells, Moran maintains his own belief that the genome is indeed overwhelmingly useless junk. "Some (I am one)," he writes, "still think that as much as 90 percent could be junk." He insists that "it's not sufficient to show that a few bits of repetitive DNA have gained a function in some species."

Dr. Moran's problem is that he has neither read Jonathan's book nor, it seems, followed the cascade of evidence from the scientific publications. It's a heck of a lot more than just "a few bits of repetitive DNA" that have been shown to be functional. In a brief (and enviably readable and accessible) 115-page book, Jonathan Wells offers over 600 references to recent peer-reviewed literature.

Twenty-five thousand studies further down the road from where we are now, no one knows how much of the genome will turn out to be truly functionless and therefore genuinely worthy of the appellation "junk." But for Darwinists, the speedily mounting evidence against junk DNA is an ominous portent. As Casey Luskin and others have put it, it's the trend that stands out prominently here, on which the likes of Larry Moran have so far been in denial.

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Genomes
& Junk DNAI've tried and tried to get the IDiots to have a serious, scientific, discussion about the evidence for and against abundant junk DNA in our genome. Some of them have tried but their arguments soon degenerate into insults about my lack of knowledge of the scientific literature. This is in spite of the fact that I have dozens of postings on the subject over the past few years and nobody has ever shown that I've been ignorant of the science behind the controversy. We may disagree about the interpretation but that's not what I'm being accused of here.

As soon as I read the book I'll post a bunch of articles pointing out why it's wrong. That will give the IDiots, like Jonathan Wells, a chance to debate the points I make and show that he is right and I am wrong. I'm looking forward to it.

4) Finally, in my own small contribution to this debate, I made a facetious comment here about how the identification of Osama bin Laden's corpse by DNA fingerprinting, using his "junk DNA" as the media habitually referred to it, provided a welcome news hook for the publication of Jonathan's book. This provoked braying responses from the Darwin Lobby. For example, our journalist friend Lauri Lebo, challenged as ever in her reading-comprehension skills, somehow understood that I was saying the usefulness of non-coding DNA for this forensic purpose proved it isn't junk.

P.Z. Myers tried to show that the usefulness of non-coding DNA for genetic fingerprinting is another demonstration that the stuff really is junk, being "subject to random changes at a higher rate than coding DNA, because it is not subject to functional constraints."

Every now and them some IDiots get something right—even if it's just by accident. One example is when Klinghoffer describes his posting as "my own small contribution."

But whether "junk DNA" is functional is exactly the question at issue, isn't it? The fact that our DNA is pervasively transcribed, as Jonathan Wells points out in Chapter 3 of his book, itself suggests pervasive functionality. As has become clear, too, DNA may serve in various functions even if it does not code for functional RNA.

It will be fun to read how Wells deals with the issue of spurious transcription based on his understanding of how RNA polymerase and transcriptional activators bind to DNA. I'm certainly looking forward to learning about the reliability of those genome studies on transcription and I'm sure Wells is going to discuss conflicting data in the scientific literature. After all, Wells has a Ph.D. in molecular biology so he must know about the real scientific controversy, right?

As for functions that don't require transcription, I highly recommend my short summary of these in What's in Your Genome. We've known about them for decades but apparently the IDiots think this is a new discovery.

So far, the Darwinist response fails to appreciate that Jonathan is in the act of very seriously blunting a Darwinian icon. What, in this context, is an icon? It's a mainstay in the public debate about Darwinian evolution that turns out, on inspection, to be based not on solid science but on puffery, illusion or deception.

This is another icon that, as Jonathan shows, was in the process of being blunted by biologists who are not ID advocates, well before Dr. Wells gathered the evidence together so concisely and conveniently in these pages.

Whatever. Wells' first book, Icons of Evolution was full of lies and I suspect this one will be too. Only one of the ten so-called icons was "blunted" by Wells and that one was the Haeckel drawings. Even then, Wells seriously distorted the significance of those fake drawings by claiming that there was now no evidence of similarities in the development of all mammals.

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65

Today is Friday the 13th. It's also my birthday! I was born in 1946. Do the math.

I have no plans to retire 'cause I'm having too much fun.

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What's in Your Genome?

The total size of the human genome is estimated to be 3.2 × 10⁹ bp [How Big Is the Human Genome?]. Here are the major components.

Transposable Elements: (44% junk)

   DNA transposons:

• active (functional): <0.1%


• defective (nonfunctional): 3%

   retrotransposons:

• active (functional):<0.1%


• defective transposons
              (full-length, nonfunctional): 8%
              L1 LINES (fragments, nonfunctional): 16%
              other LINES: 4%
              SINES (small pseudogene fragments): 13%


• co-opted transposons/fragments: <0.1% ^a

  ^aCo-opted transposons and transposon fragments are those that have secondarily acquired a new function.

Viruses (9% junk)

   DNA viruses

• active (functional): <0.1%


• defective DNA viruses: ~1%

   RNA viruses

• active (functional): <0.1%


• defective (nonfunctional): 8%


• co-opted RNA viruses: <0.1% ^b

  ^bCo-opted RNA viruses are defective integrated virus genomes that have secondarily acquired a new function.

Pseudogenes (1.2% junk)

• (from protein-encoding genes): 1.2% junk
• co-opted pseudogenes: <0.1% ^c

  ^cCo-opted pseudogenes are formerly defective pseudogenes those that have secondarily acquired a new function.

Ribosomal RNA genes:

• essential 0.22%
• junk 0.19%

Other RNA encoding genes

• tRNA genes: <0.1% (essential)


• known small RNA genes: <0.1% (essential)


• putative regulatory RNAs: ~2% (essential)

Protein-encoding genes: (9.6% junk)

• transcribed region:
              essential 1.8%
              intron junk (not included above) 9.6% ^d

  ^dIntrons sequences account for about 30% of the genome. Most of these sequences qualify as junk but they are littered with defective transposable elements that are already included in the calculation of junk DNA.

Regulatory sequences:

• essential 0.6%

Origins of DNA replication

• <0.1% (essential)

Scaffold attachment regions (SARS)

• <0.1% (essential)

Highly Repetitive DNA (2% junk)

• α-satellite DNA (centromeres)
• essential 1.0%
• non-essential 2.0%
• telomeres
• essential (less than 1000 kb, insignificant)

Intergenic DNA (not included above)

• conserved 2% (essential)
• non-conserved 26.3% (unknown but probably junk)

Theme Genomes & Junk DNATotal Essential/Functional (so far) = 7.7% Total Junk (so far) = 65% Unknown (probably mostly junk) = 27.3%

For references and further information click on the "Genomes & Junk DNA" link in the box

LAST UPDATES: May 10, 2011 (fixed totals, and ribosomal RNA calculations)
June 3, 2011 (added total genome size)
February 5, 2013 (reformatted)

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Junk & Jonathan: Part 3—The Preface

Here's the preface to The Myth of Junk DNA by the IDiot, Jonathan Wells. After each paragraph I've inserted a short version of the truth just so you don't get misled by all the untruths and distortions that are found in creationist books.

See:

Junk & Jonathan: Part I—Getting the History Correct

Junk & Jonathan: Part 2— What Did Biologists Really Say About Junk DNA?

Jonathan, Moonies, and Junk DNA

The discovery in the 1970s that only a tiny percentage of our DNA codes for proteins prompted some prominent biologists at the time to suggest that most of our DNA is functionless junk. Although other biologists predicted that non-protein-coding DNA would turn out to be functional, the idea that most of our DNA is junk became the dominant view among biologists.

• It's true that in the 1970s the experts in the study of genomes proposed that most of our genome is junk.
• It's not true that they thought non-coding DNA had no function. Functions of non-coding DNA were well-established by 1970.
• The idea that most of our genome is junk was never the "dominant" view among biologists even though it's correct.

That view has turned out to be spectacularly wrong. Since 1990--and especially after completion of the Human Genome Project in 2003--many hundreds of articles have appeared in the scientific literature documenting the various functions of non-protein coding DNA, and more are being published every week.

• It's not true that the idea of a large amount of junk DNA has turned out to be "spectacularly wrong."
• It's true that there have been lots of examples of of novel functions for small pieces of the genome that were previously lumped into the junk DNA category. These dozens of functional parts of the genome may amount to as much as 1-2% of the genome (probably less).

Ironically, even after evidence for the functionality of non-protein coding DNA began flooding into the scientific literature, some leading apologists for Darwinian evolution ratcheted up claims that "junk DNA" provides evidence for their theory and evidence against intelligent design. Since 2004, biologists Richard Dawkins, Douglas Futuyma, Kenneth Miller, Jerry Coyne and John Avise have published books using this argument. So have philosopher of science Philip Kitcher and historian of science Michael Shermer. So has Francis Collins, former head of the Human Genome Project and present director of the National Institutes of Health, despite the fact that he co-authored some of the scientific articles providing evidence against "junk DNA."

• It's true that well-established bits of junk DNA—like known pseudogenes—have been effectively used to challenge the idea that our genome appears designed. Those examples remain powerful, and true, examples of evolution that cannot be explained by Intelligent Design Creationism. They have not been refuted and they have not been explained by the IDiots.

These authors claim to speak for "science," but they have actually been promoting an anti-scientific myth that ignores the evidence and relies on theological speculations instead. For the sake of science, it's time to expose the myth for what it is.

• The truth is that those authors still speak for science and truth and their evidence is sound.
• Wells, on the other hand, speaks for the other side.

Theme

Genomes
& Junk DNA

Far from consisting mainly of junk that provides evidence against intelligent design, our genome is increasingly revealing itself to be a multidimensional, integrated system in which non-protein-coding DNA performs a wide variety of functions. If anything, it provides evidence for intelligent design. Even apart from possible implications for intelligent design, however, the demise of the myth of junk DNA promises to stimulate more research into the mysteries of the genome. These are exciting times for scientists willing to follow the evidence wherever it leads.

• It's certainly true that non-coding DNA performs a wide variety of functions. Some of them are listed in various postings under Genomes & Junk DNA
• It's certainly not true that the organization of our genome—the majority of which is junk—provides evidence of intelligent design.
• It's certainly not true that the idea of junk DNA is a myth.
• It's true that these are exciting times and that smart people must follow the evidence wherever it leads even if it refutes cherished religious beliefs.

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[Hat Tip: Preface to The Myth of Junk DNA by Jonathan Wells]

Carnival of Evolution #35

This month's Carnival of Evolution (35th version) is hosted by Lab Rat at Lab Rat [The Carnival is here!]. ("Lab Rat" isn't really a rat. She's a biochemistry undergraduate who works on bacteria.)

Here are the subtitles ...

• The Ecologists


• The Plant Scientists


• The Computer Scientists


• The Microbiologists


• The Medical Scientists


• The Archaeologists and Anthropologists


• The Social and Political Scientists

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Teaching Evolution: Are Geoscience Teachers Helping or Hurting?

The National Center for Science Education (NCSE) is promoting a position statement on evolution issued by the National Association of Geoscience Teachers (NAGT) [Geoscience teachers add their voice for evolution]. Apparently NCSE thinks this statement is good enough to include on their website and and publish in the next edition of Voices for Evolution. The statement can be found on the NAGT website: Position Statement - Teaching Evolution. It was published in 2006. I'm reproducing it below in order to get your opinion.

Is this statement helpful in understanding evolution and in teaching the concept correctly in high school science classes? I don't think so. I think it only adds to the confusion by conflating biological evolution with all kinds of change including geologic change. I think there's a big difference between understanding how the Hawaiian islands might have formed and why all living species have descended from a common ancestor. I think the "scientific theory of evolution" refers to biological evolution and it doesn't help when high school science teachers equate that to geologic change and cultural change.

The National Association of Geoscience Teachers (NAGT) recognizes that the scientific theory of evolution is a foundational concept of science, and therefore must also be a cornerstone of science education. Evolution in the broadest sense refers to any change over time. The study of Earth's evolution provides society with the time and space perspectives necessary to understand how Earth's physical and biological processes developed, provides insight into the natural processes active on Earth, and shapes our view of Earth's future.

Evolutionary studies apply to most branches of science, including organic evolution, cosmic evolution, geologic evolution, planetary evolution, and cultural evolution. Each of these subdisciplines of science provides evidence that evolution is pervasive: galaxies have changed, stars and planets have changed, Earth has changed, life forms on Earth have changed, and human culture has changed. Evolution is therefore factual and is a unifying concept of the natural sciences. For this reason, the National Science Education Standards (NRC), Benchmarks for Science Literacy (AAAS), numerous national education policy documents, and individual states, through their published science education frameworks, all recognize that evolution is a unifying concept for science disciplines and provides students with the foundation to help them understand the natural world. NAGT fully agrees with and supports the scientific validity of evolution as reflected in the position statements of the numerous scientific societies that unanimously support evolution on scientific grounds. NAGT further maintains that the scientific theory of evolution should be taught to students of all grade levels as a unifying concept without distraction of non-scientific or anti-scientific influence.

Published and reaffirmed position statements on the scientific validity of evolution by all of the scientific societies clearly demonstrate that the modern scientific community no longer debates whether evolution has occurred. Scientific investigation of the mechanisms of evolution and the interconnected "details" of mechanism, process, history, and outcome remain at the current scientific forefront of evolutionary studies. This is the nature of scientific inquiry itself: to continually evaluate scientific theories with an eye towards improving our scientific models and adding more details to our understanding of the natural world. Scientists often disagree about explanations of how evolution works, the importance of specific evolutionary processes, or the patterns that are observed, but all agree that evolution has occurred and is occurring now. Global change will be the future projection of past and ongoing evolutionary processes. While evolution is factual, evolution is also a "scientific theory", which is an explanation for the observed changes. This usage of theory should not be confused with the non-scientific usage of theory as an ad-hoc idea unsupported by testing or evidence.

In science, disagreements are subject to rules of scientific evaluation, and this includes the methodologies of teaching scientific concepts. Scientific conclusions are tested by experiment, observation, and evaluation. Sound practices of scientific education are tested and evaluated much the same way. NAGT recognizes that invoking non-naturalistic or supernatural events or beings, often guised as "creation science," "scientific creationism," or "intelligent design theory," are not scientific in character, do not conform to the scientific usage of the word theory, and should not be part of valid science curricula.

As stated in NAGT's Constitution, the purpose of the NAGT is to foster improvements in the teaching of the earth sciences at all levels of formal and informal instruction, to emphasize the relevance and cultural significance of the earth sciences, and to disseminate knowledge in this field to educators and the general public. The NAGT fully accepts its role in the evaluation and betterment of the teaching of scientific evolution in formal and informal educational settings, with the explicit goal of helping everyone to understand the scientific merit this fundamental concept has in modern science. The Journal of Geoscience Education publishes papers related to research concerning the pedagogy, assessment, history, philosophy and culture of teaching and learning about the geosciences, especially of fundamental concepts like geologic time and faunal and stratigraphic succession, all aspects of evolution.

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Pray for Texas

TO ALL TO WHOM THESE PRESENTS SHALL COME:

WHEREAS, the state of Texas is in the midst of an exceptional drought, with some parts of the state receiving no significant rainfall for almost three months, matching rainfall deficit records dating back to the 1930s; and

WHEREAS, a combination of higher than normal temperatures, low precipitation and low relative humidity has caused an extreme fire danger over most of the State, sparking more than 8,000 wildfires which have cost several lives, engulfed more than 1.8 million acres of land and destroyed almost 400 homes, causing me to issue an ongoing disaster declaration since December of last year; and

WHEREAS, these dire conditions have caused agricultural crops to fail, lake and reservoir levels to fall and cattle and livestock to struggle under intense stress, imposing a tremendous financial and emotional toll on our land and our people; and

WHEREAS, throughout our history, both as a state and as individuals, Texans have been strengthened, assured and lifted up through prayer; it seems right and fitting that the people of Texas should join together in prayer to humbly seek an end to this devastating drought and these dangerous wildfires;

NOW, THEREFORE, I, RICK PERRY, Governor of Texas, under the authority vested in me by the Constitution and Statutes of the State of Texas, do hereby proclaim the three-day period from Friday, April 22, 2011, to Sunday, April 24, 2011, as Days of Prayer for Rain in the State of Texas. I urge Texans of all faiths and traditions to offer prayers on that day for the healing of our land, the rebuilding of our communities and the restoration of our normal way of life.

IN TESTIMONY WHEREOF, I have hereunto signed my name and have officially caused the Seal of State to be affixed at my Office in the City of Austin, Texas, this the 21st day of April, 2011.

RICK PERRY
Governor of Texas

This is going to put God in a really difficult position. He's right in the middle of punishing Texas for being so stupid in the past few decades and now the Texans are pleading for relief from that punishment. It may be hopeless. After all, the Egyptians didn't get spared when they prayed to their gods to stop another god from killing all their firstborn sons.

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[Office of the Governor]

The Student-Centered Classroom

A large part of the AAAS document, Vision and Change in Undergraduate Biology Education is devoted to how to teach science. The "core concepts" take up only 2 pages out of 79 pages in the booklet.

The modern buzzword phrase for the 21st century is "The Student-Centered Classroom" and "Student-Centered Learning." The terms means lot of different things to different people but the key concept is to move away from lecturing about "facts" to a classroom format that emphasizes student participation in the learning process.

Although the definition of student-centered learning may vary from professor to professor, faculty generally agree that student-centered classrooms tend to be interactive, inquiry driven, cooperative, collaborative, and relevant. Three critical components are consistent throughout the literature, providing guidelines that faculty can apply when developing a course. Student centered courses and curricula take into account student knowledge and experiences at the start of a course and articulate clear learning outcomes in shaping instructional design. Then they provide opportunities for students to examine and discuss their understanding of the concepts presented, offering frequent and varied feedback as part of the learning process. As a result, student-centered science classrooms and assignments typically involve high levels of student–student and student–faculty interaction; connect the course subject matter to topics students find relevant; minimize didactic presentations; reflect diverse aspects of scientific inquiry, including data interpretation, argumentation, and peer review; provide ongoing feedback to both the student and professor about the student’s learning progress; and explicitly address learning how to learn.

This is a very good idea in theory but putting it into practice is much harder than it looks. I've seen some excellent examples of student-centered learning at various conferences over the past few years. One type of student-centered learning seems particularly attractive to me and I've tried it several times in my courses. Here's how it's described in the Vision and Change document (p. 26).

Typically, these strategies engage students more actively in every aspect of their learning and are interactive, inquiry driven, cooperative, and collaborative, allowing students to engage with each other and with faculty. For example, the “problem–based model of instruction,” or learning cycle (Bybee, 1997; Fuller, 2002), revolves around a series of related questions that first probe what students know about a topic and then move to unfamiliar, new ground, enabling the students to develop a more complete and accurate understanding of the topic. Faculty initiate student interactions with key guiding questions and opportunities for discussion, present a short explanation of the necessary background knowledge, and then have students work together on questions to deepen their understanding through reflection on and application of their knowledge (e.g., Ebert-May et al., 1997). This approach incorporates frequent informal assessment (e.g., Angelo and Cross, 1992) to address misconceptions and provides a balance between direct instruction and student interaction. One or two class sessions using this approach to introduce a topic such as evolution might unfold in the following way (e.g., Ebert-May et al., 2008):

1. Engagement Question: For example, “What is evolution?” This background question probes student knowledge of the topic.
2. Exploration: Students share their answers with other students sitting nearby and come to a consensus; volunteers from the groups share their answer with the class, allowing the instructor to listen for misconceptions and depth of understanding.
3. Explanation: The instructor presents a short interactive lecture (15 minutes) on the topic, providing explanations to help clarify student thinking based on identified misconceptions.
4. Extension Question: Students work together on a more advanced question that might, for example, call for them to analyze information, formulate critical questions and hypotheses, evaluate and criticize evidence, or propose alternative solutions. In the example of evolution, the extension question, tied to a learning goal, might be What mechanisms are involved in natural selection, and what role does natural selection play in antibiotic resistance in bacteria today? Again, groups are called on to explain their answers and how they came to them.
5. Quiz Question: The final assessment (which may or may not be formally graded) allows both the student and the instructor to chart the effectiveness of teaching and learning.

The idea here is to confront misconceptions by having students come up with their own ideas about answering the "engagement question." This gives the instructor the opportunity to correct the most common misconceptions. In this example, the students will almost certainly come up with a definition of evolution that requires natural selection and excludes random genetic drift. They will frequently include mutation and recombination as part of their definition. Most of the time students will demonstrate lack of knowledge of population genetics.

The lecture component will explain the reasoning behind different definitions of evolution and why one might prefer one definition over another. Part of the explanation involves creating a "minimal definition" of evolution that will allow one to distinguish between evolution and something else. (I choose human examples. Think about the increased height in Europeans over the past 500 years. Is that evolution? Why or why not? Why do some native North American populations have only O-type blood? Is that evolution?)

The "extension question" should be designed to challenge students to think about the topic in new ways. In my case, the extension question is often something like this ...

If evolution is defined as a change in the frequency of alleles in a population and if fixation of alleles can occur by several different mechanisms, then what is the most common mechanism of evolution according to the data we have?

I think the three most important criteria in science education are (1) accuracy, (2) accuracy, and (3) accuracy. Everything else is of lesser importance, including how you teach the concept. Thus, you may be an expert at student-centered learning but if you don't understand evolution then the exercise is completely ineffective no matter how much the students may enjoy it.

If we are going to fix undergraduate education in biology then we need to concentrate above all else on making sure we accurately identify the core concepts and make sure they are being taught correctly. We can move on to other things once we are convinced that the first three objectives (accuracy, accuracy, and accuracy) are being achieved. It could actually be harmful to develop a student-centered learning course based on false concepts.

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Core Concepts: Pathways and Transformations of Energy and Matter

The AAAS document, Vision and Change in Undergraduate Biology Education, defines five core concepts for biological literacy. One of the core concepts is Pathways and Transformations of Energy and Matter. This is an important one for biochemistry since we are the people charged with making sure undergraduates understand the basic core concept that life obeys the laws of physics and chemistry.

Here's how the authors of Vision and Change describe the core concept.

4. PATHWAYS AND TRANSFORMATIONS OF ENERGY AND MATTER:

Biological systems grow and change by processes based upon chemical transformation pathways and are governed by the laws of thermodynamics.

The principles of thermodynamics govern the dynamic functions of living systems from the smallest to the largest scale, beginning at the molecular level and progressing to the level of the cell, the organism, and the ecosystem. An understanding of kinetics and the energy requirements of maintaining a dynamic steady state is needed to understand how living systems operate, how they maintain orderly structure and function, and how the laws of physics and chemistry underlie such processes as metabolic pathways, membrane dynamics, homeostasis, and nutrient cycling in ecosystems. Moreover, modeling processes such as regulation or signal transduction requires an understanding of mathematical principles.

For example, knowledge of chemical principles can help inform the production of microorganisms that can synthesize useful products or remediate chemical spills, as well as the bioengineering of plants that produce industrially important compounds in an ecologically benign manner. These are topics of intense current interest.

At first glance this seems like an adequate description of a core concept but the more you think about it the more you realize that it's just a bunch of motherhood statements without any real teeth. It sounds very nice to say that students need to understand kinetics and thermodynamics but the recommendation has no substance unless you explain exactly what it is that they are supposed to understand. We all know that both these concepts are poorly taught in undergraduate courses.

When I was teaching introductory biochemistry I always asked my students the following question to make sure they had grasped the concept of where cellular energy comes from.

There are species that are autotrophs. They grow and reproduce using only inorganic molecules as their only source of essential elements. Carbon usually comes from CO₂. Some of these species are capable of photosynthesis (photoautotrophs) but others are not (chemoautotrophs). Where do chemoautotrophs get the energy to grow and reproduce if they can't carry out photosynthesis and they don't require organic molecules as food sources?

Let's look at the AAAS Project 2061 Science Assessment Website to see how they treat the topic of Matter and Energy in Living Systems. This site is for high school biology but it's the only place I know where we can assess what AAAS thinks is important in basic concepts. Students are expected to know that...

All organisms need food as a source of molecules that provide chemical energy and building materials.

1. Food consists of carbon-containing molecules in which carbon atoms are linked to other carbon atoms.
2. Carbon-containing molecules serve as the building materials that all organisms (including plants and animals) use for growth, repair, and replacement of body parts (such as leaves, stems, roots, bones, skin, muscles, and the cells that make up these structures) and provide the chemical energy needed to carry out life functions.
3. If substances do not provide both chemical energy and building material, then they are not food for an organism.
4. Chemical energy from carbon-containing molecules is the only form of energy that organisms can use for carrying out life functions.
5. Carbohydrates (including simple sugars and starch), fats, and proteins are molecules that are food.
6. Light is not food because it is not made of atoms and therefore cannot provide building material, and even though substances such as water, carbon dioxide, oxygen, and various minerals provide atoms for building materials for some types of organisms, they are not food because they do not contain carbon atoms that are linked to other carbon atoms and cannot be used as a source of chemical energy.

Oh dear. If this is an example of core concepts then we need to add one more item; namely "7. According to item #3, chemoautotrophs are not organisms."

I'm sure most of you recognize the problem. The focus is on plants and animals, ignoring protozoa and bacteria. This is not how to teach basic concepts in biology and it certainly isn't how to teach if evolution is supposed to be an important core concept. Complex plants and animals did not just poof into existence with specialized metabolic pathways.

But not to worry. Although the six statements above seem wrong, they are soon clarified in the next section ...

Plants make their own food in the form of sugar molecules from carbon dioxide molecules and water molecules. In the process of making sugar molecules, oxygen molecules are produced as well.

1. Unlike animals, plants do not take in food from their environment.
2. Plants make their own food in the form of sugar molecules by means of a chemical reaction between carbon dioxide molecules and water molecules. Oxygen molecules are also a product of this reaction.
3. The process of making sugar molecules involves linking together carbon atoms that come from molecules of carbon dioxide.
4. The chemical reactions by which sugars are made takes place inside the plants. In most familiar land plants, the carbon dioxide molecules that are used come from the air that enters the plant primarily through its leaves, and that the water molecules that are used in the reaction enter the plant through its roots.

Here's the core concept as I teach it. I'd appreciate feedback on which way is better.

Photosynthetic organisms, such as bacteria, algae, and plants, can use light as a source of energy. They convert this energy into chemical energy in the form of ATP and other cofactors. These "high energy" molecules are used to provide energy in biosynthesis reactions that make all of the important molecules in the cell including amino acids, proteins, nucleotides, nucleic acids, fatty acids, lipids & membranes, carbohydrates, and polysaccharides.

Note that point #2 above is absolutely wrong. Oxygen is NOT produced as a result of a reaction between CO₂ and H₂O. That is a major misconception. The oxygen given off by some photosynthetic species is derived directly from water as part of the photosynthetic electron transfer reactions. Some photosynthetic species don't produce oxygen yet they are perfectly capable of synthesizing nucleic acids, proteins, lipids, and carbohydrates. How do they do it? You need to understand the answer to that question if you are going to understand how eukaryotic photosynthesis evolved.

My main criticism of undergraduate biology education is that the core concepts are not being taught and, when an attempt is made, they are often taught incorrectly. The Vision and Change document doesn't make a contribution toward fixing this problem. The "core concepts" it describes are not specific enough to be helpful and when they are specific they turn out to be wrong or misleading.

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Vote for Omar

Here's the latest video from the Liberal Candidate in my riding. These videos are one of the many reasons why I'm going to vote for him.

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AAAS Flunks Evolution!

As I noted yesterday, the AAAS document, Vision and Change in Undergraduate Biology Education, defines five core concepts for biological literacy [Core Concepts: Evolution]. Evolution is the first core concept and this is a very good thing. Congratulations to the committee for a wise choice.

However, the way that the core concept is described was troubling. It suggested to me that the members of the committee may not understand evolution as well as they think they do. This worry is reinforced by the AAAS Project 2061 Science Assessment Website where a series of questions and responses about evolution indicates that AAAS flunks the test.

There's no mention of the standard definition of evolution as a change in the heritable characteristics of a population over time [What Is Evolution?]. This is important because a fundamental part of the core concept is the understanding that any mechanism of change counts as evolution—not just natural selection. Another fundamental part of evolution is understanding that it is populations that evolve and not individuals. The population genetics definition of evolution was developed in the 1930s and became a key part of the Modern Synthesis in the 1940s. The definition is almost 70 years old. Why don't the authors of the report know this?

There's no mention of random genetic drift. The assessment questions are all about natural selection. In fact, the key topic concept is called "Evolution and Natural Selection." How are students supposed to understand phylogenetic trees based on sequences if they don't understand the basic stochastic process that generates these trees? How are they supposed to understand genetic variation if they've never heard of neutral mutations and how they can be fixed by random genetic drift?

There's nothing about mutation. Don't students need to understand mutation in order to understand variation? Of course they do.

There's nothing about speciation. Understanding how new species arise is an important part of evolution.

The problem with the Vision and Change document is that it identifies five core concepts but it doesn't tell us what they are beyond giving them names. If you want to reform undergraduate teaching you have to not only identify what the core concepts are but also make sure they are accurate. If you don't understand the core concepts to begin with then you aren't going to teach them properly to your students. I don't think most professors understand evolution well enough to be able to teach it effectively as a core concept. (This also applies to the other core concepts as I will explain over the next few days.)

What we really need is a committee that examines how to teach PROFESSORS the core concepts of biology. Unfortunately, ignorance of the core concept of evolution is widespread and seems to include many of the professors who created the Vision and Change document.

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