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Friday, November 20, 2015

Different kinds of pseudogenes: Unitary pseudogenes

The most common types of pseudogenes are processed pseudogenes and those derived from gene duplication events [duplicated pseudogenes].

The third type of pseudogene is the "unitary" pseudogene. Unitary pseudogenes are genes that have no parent gene. There is no functional gene in the genome that's related to the pseudogene.

Unitary psedogenes arise when a normally functional gene becomes inactivated by mutation and the loss of function is not detrimental to the organism. Thus, the mutated, inactive, gene can become fixed in the population by random genetic drift.

The classic example is the gene for L-glucono-γ-lactone oxidase (GULO), a key enzyme in the synthesis of vitamin C (L-ascorbate, ascorbic acid). This gene is functional in most vertebrate species because vitamin C is required as a cofactor in several metabolic reactions; notably, the processing of collagen [Vitamin C]. This gene has become inactive in primates so primates cannot synthesize Vitamin C and must obtain it from the food they eat.

A pseudogene can be found at the locus for the L-glucono-γ-lactone oxidase gene[GULOP = GULO Pseudogene]. It is a highly degenerative pseudogene with multiple mutations and deletions [Human GULOP Pseudogene]


This is a unitary pseudogene. Unitary pseudogenes are rare compared to processed pseudogenes and duplicated pseudogenes but they are distinct because they are not derived from an existing, functional, parent gene.

Note: Intelligent design creationists will go to great lengths to discredit junk DNA. They will even attempt to prove that the GULO pseudogene is actually functional. Jonathan Wells devoted an entire chapter in The Myth of Junk DNA to challenging the idea that the GULO pseudogene is actually a pseudogene. A few years ago, Jonathan McLatchie proposed a mechanism for creating a functional enzyme from the bits and pieces of the human GULOP pseudogene but that proved embarrasing and he retracted [How IDiots Would Activate the GULO Pseudogene] Although some scientists are skeptical about the functionality of some pseudogenes, they all accept the evidence showing that most psuedogenes are nonfunctional.


Different kinds of pseudgogenes: Duplicated pseudogenes

Of the three different kinds of pseudogenes, the easiest kind of pseudogene formation to understand is simple gene duplication followed by inactivation of one copy. [see: Processed pseudogenes for another type]

I've assumed, in the example shown below, that the gene duplication event happens by recombination between sister chromosomes when they are aligned during meiosis. That's not the only possibility but it's easy to understand.

These sorts of gene duplication events appear to be quite common judging from the frequency of copy number variations in complex genomes (Redon et al., 2006; MacDonald et al., 2013).


Wednesday, November 18, 2015

Different kinds of pseudogenes: Processed pseudogenes

Let's look at the formation of a "processed" pseudogene. They are called "processed" because they are derived from the mature RNA produced by the functional gene. These mature RNAs have been post-transcriptionally processed so the pseudogene resembles the RNA more closely than it resembles the parent gene.

This is most obvious in the case of processed pseudogenes derived from eukaryotic protein-coding genes so that's the example I'll describe first.

In the example below, I start with a simple, hypothetical, protein-coding gene consisting of two exons and a single intron. The gene is transcribed from a promoter (P) to produce the primary transcript containing the intron. This primary transcript is processed by splicing to remove the intron sequence and join up the exons into a single contiguous open reading frame that can be translated by the protein synthesis machinery (ribosomes plus factors etc.).1 [See RNA Splicing: Introns and Exons.]

Different kinds of pseudogenes - are they really pseudogenes?

I define a gene as "DNA sequence that is transcribed to produce a functional product" [What Is a Gene? ]. Genes can encode proteins or the final product can be a functional RNA other than mRNA.

A pseudogene is a broken gene that cannot produce a functional RNA. They are called "pseudogenes" because they resemble active genes but carry mutations that have rendered them nonfunctional. The human genome contains about 14,000 pseudogenes related to protein-coding genes according to the latest Ensembl Genome Reference Consortium Human Genome build [GRCh38.p3]. There's some controversy over the exact number but it's certainly in that ballpark.1

The GENCODE Pseudogene Resource is the annotated database used by Ensembl and ENCODE (Pei et al. 2012).

There are an unknown number of pseudogenes derived from genes for noncoding functional RNAs. These pseudogenes are more difficult to recognize but some of them are present in huge numbers of copies. The Alu elements in the human genome are derived from 7SL RNA and there are similar elements in the mouse genome that are derived from tRNA genes.

There are three main classes of pseudogenes and one important subclass. The categories apply to pseudogenes derived from protein-coding genes and to those derived from genes that specify functional noncoding RNAs. I'm going to describe each of the categories in separate posts. I'll mostly describe them using a protein-coding gene as the parent.

1. Processed pseudogenes [Processed pseudogenes ]
2. Duplicated pseudogenes [Duplicated pseudogenes ]
3. Unitary pseudogenes [Unitary Pseudogenes]
4. subclass: Polymorphic pseudogenes [Polymorphic Pseudogenes]

Saturday, November 14, 2015

Which animals have barely evolved according to National Geographic?

Liz Langley of National Geographic has posted an article on their website: Which Animals Have Barely Evolved?.

The answers are the platypus and the opossum. The overall impression she conveys to the general public is that these species have not evolved for millions and millions of years.

I don't agree. I think it's important to teach the general public that such statements flatly contradict modern evolutionary theory. If, in fact, we discovered modern species that showed no signs of having evolved for millions of years, this would refute modern evolutionary theory.

The accepted minimal definition of evolution is ... [What Is Evolution?]
Evolution is a process that results in heritable changes in a population spread over many generations.
... or something similar like "change in the frequency of alleles in a population."

The main accepted mechanisms of evolution are natural selection and random genetic drift.

The only way positive natural selection1 can stop is if an organism is so perfectly adapted to its current environment (external and internal) that every possible mutation is either deleterious or neutral. That includes all metabolic processes and every structure in the cell.

Nobody could rationally advocate such a claim.

The only way to stop random genetic drift is if there's no such thing as a new neutral or nearly neutral mutation and all such variation in the population has been eliminated.

No evolutionary biologist could possibly make such a claim with a straight face.

It's easy to test such ridiculous claims by looking at the genomes of the opossum and the platypus. The evidence shows that they have evolved at the same rate as all other species.

The article actually mentions this problem ...
“'Unchanged' is a tricky word,” Nizar Ibrahim, a paleontologist at the University of Chicago and 2014 National Geographic Explorer, says via email.

With only fossils to go by, scientists can examine an ancient animal's skeletal structure, but it's not the whole story. Physiology and DNA change somewhat over time, he says, both through the basic process of evolution as well as random genetic changes.

That said, two mammals that have undergone the fewest evolutionary shifts are the platypus and the opossum, says Samantha Hopkins, associate professor of geology at the University of Oregon.
Liz Langley did not pick up on this comment so she missed a wonderful teaching moment.

It's possible that Liz Langley isn't aware of modern evolutionary theory and that she actually believes that evolution comes to a halt as long as species live in a relatively constant environment. It's possible that she disagrees with the minimal definition of evolution and prefers a definition that only counts significant changes in external phenotype. Or, it's possible that she thinks that National Geographic readers can't handle modern evolutionary theory. If it's the latter, I disagree.


1. You can't stop negative natural selection unless there are no new deleterious mutations. That's also impossible.

Friday, November 13, 2015

Cornelius Hunter predicts that there's going to be function found for the vast majority of the genome according to the intelligent design paradigm

Listen to this Podcast where Casey Luskin interviews Dr. Cornelius Hunter.1 It's only 9 minutes long.

Dr. Cornelius Hunter on ENCODE and "Junk" DNA, Part 2

Here's part of the transcript.
Casey Luskin: ... and, as we all know, or many ID the Future listeners probably know, for years Darwinian theorists and evolutionary scientists have said that our genomes ought to be full of junk if evolution is true

.....

Casey Luskin: So, Dr. Hunter, you think, just for the record, that in the long term there is going to be function found for probably the vast majority of the genome and so, maybe, you might call it a prediction you would make coming out of an intelligent design paradigm. Is that correct?

Cornelius Hunter: Yes, that's correct Casey, I'll definitely go on the record on that. Not to say I have a hundred percent confidence and also I wanna be clear that from a metaphysical perspective, from my personal belief, I don't have a problem wherever it lands. It doesn't matter to me whether it's 10% or 90% or any where in between or 100% ... just from the scientific perspective and just from the history of science and the history of what we've found in biology, it really does look like it's gonna be closer to 100 than zero.

Casey Luskin: Okay, great, I always like it when people put clear and concrete predictions out there and and I think that's very helpful.

I predict that about 90% of our genome will turn out to be junk DNA—DNA with no function. I base my prediction on the scientific perspective and the history of what we've found in biology. That's interesting because Cornelius Hunter and I are apparently reaching opposite conclusions based on the same data.

I also love it when people make predictions. Will the intelligent design paradigm be falsified if I turn out to be right?

Does it sound to you that Cornelius Hunter personally doesn't care if the prediction coming out of the intelligent design paradigm is correct or not?


1. How come in the podcast they never refer to Dan Graur as Dr. Graur? Isn't that strange?

The 2015 Nobel Prize in Chemistry: was the history of the discovery of DNA repair correct?

... those ignorant of history are not condemned to repeat it; they are merely destined to be confused.

Stephen Jay Gould
Ontogeny and Phylogeny (1977)
Back when the Nobel Prize in Chemistry was announced I was surprised to learn that it was for DNA repair but Phil Hanawalt wasn't a winner. I blogged about it on the first day [Nobel Prize for DNA repair ].

I understand how difficult it is to choose Nobel Laureates in a big field where a great many people make a contribution. That doesn't mean that the others should be ignored but that's exactly what happened with the Nobel Prize announcement [The Nobel Prize in Chemsitry for 2015].
In the early 1970s, scientists believed that DNA was an extremely stable molecule, but Tomas Lindahl demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible. This insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA.
Maybe it's okay to ignore people like Phil Hanawalt and others who worked out mechanisms of DNA repair in the early 1960s but this description pretends that DNA repair wasn't even discovered until ten years later.

I published links to all the papers from the 1960s in a follow-up post [Nature publishes a misleading history of the discovery of DNA repair ].

By that time I was in touch with David Kroll who was working on an article about the slight to early researchers. He had already spoken to Phil Hanawalt and discovered that he (Hanawalt) wasn't too upset. Phil is a really, really nice guy. It would be shocking if he expressed disappointment or bitterness about being ignored. I'll do that for him!

The article has now been published: This Year’s Nobel Prize In Chemistry Sparks Questions About How Winners Are Selected.

Read it. It's very good.


Wednesday, November 11, 2015

Pwned by lawyers (not)

A few days ago I mentioned a post by Barry Arrington where he said, "You Should Know the Basics of a Theory Before You Attack It. I pointed out the irony in my post.

Barry Arringotn took exception and challenged me in: Larry Moran's Irony Meter.
OK, Larry. I assume you mean to say that I do not understand the basics of Darwinism. I challenge you, therefore, to demonstrate your claim.
This was the kind of challenge that's like shooting fish in a barrel but I thought I'd do it anyway in case it could serve as a teaching moment. Boy, was I wrong! Turns out that ID proponents are unteachable.

I decided to concentrate on Arrington's published statements about junk DNA where he said ...

Stephen Jay Gould talks about the fossil record and creationists

I was alerted to this video by a post on Facebook. I had never seen it before. The occasion is the celebration of the 20th anniversary of McLean v. Arkansas— one of the legal victories of Americans who are fighting to keep creationism out of the classroom.

It's a 30 minute presentation by Stephen J. Gould on the fossil record. The event took place in February 2001, just a year before he died. You should watch it for many reasons—too many to mention them all here but here are some of the most important ones.

Genie Scott says in the introduction ...

Monday, November 09, 2015

How many proteins do humans make?

There are several different kinds of genes. Some of them encode proteins, some of them specify abundant RNAs like tRNAs and ribosomal RNAs, some of them are responsible for making a variety of small catalytic RNAs, and some unknown fraction may specify regulatory RNAs (e.g. lncRNAs).

This jumble of different kinds of genes makes it difficult to estimate the total number of genes in the human genome. The current estimates are about 20,000 protein-coding genes and about 5,000 genes for functional RNAs.

Aside from the obvious highly conserved genes for ubiquitous RNAs (rRNA, tRNAs etc.), protein-coding genes are the easiest to recognize from looking at a genome sequence. If the protein is expressed in many different species then the exon sequences will be conserved and it's easy for a computer program to identify the gene. The tough part comes when the algorithm predicts a new protein-coding gene based on an open reading frame spanning several presumed exons. Is it a real gene?

Sunday, November 08, 2015

Answering Barry Arrington's challenge: Darwinism predicted junk DNA

In my first post [Answering Barry Arrington's challenge: Darwinism] I established that Barry Arrington's version of "Darwinism" is actually "Neo-Darwinism" or the "Modern Synthesis." We all know why Intelligent Design Creationists would rather use "Darwinism"—this explains why they deliberately change the meaning to make it look like they understand evolution

Arrington's version of "Darwinism can be seen in the Uncommon Descent glossary. It focuses on natural selection as the mechanism of evolution and doesn't mention Neutral Theory of random genetic drift.

Barry Arrington's challenge to me is ...

Answering Barry Arrington's challenge: Darwinism

I posted something yesterday about Barry Arrington and irony [You should know the basics of a theory before you attack it]. This got Barry Arringon's attention so he put up his own blog post [Larry Moran’s Irony Meter] where he issues a challenge ....
OK, Larry. I assume you mean to say that I do not understand the basics of Darwinism. I challenge you, therefore, to demonstrate your claim.
Today I'm feeling optimistic—life is good and this evening we're going to a nice restaurant for dinner with our favorite nephew.1 Let's try, once again, to convert this into a teaching moment. Hopefully, at least one or two ID proponents will learn something.2

What do they mean by "Darwinism"?

Saturday, November 07, 2015

You should know the basics of a theory before you attack it

Turn off your irony meters. Really ... I'm not kidding. They will never survive if you leave them on and follow the link to this post by Barry Arrington on Uncommon Descent.

Don't say I didn't warn you!

You Should Know the Basics of a Theory Before You Attack It
The answer, of course, is “nothing.” Having studied Darwinism for over 20 years, I can tell you what it posits. Therefore, when I attack it, I am attacking the actual thing, not some distortion of the thing that exists nowhere but my own mind.


God's Not Dead the sequel is coming soon - save the date

Oh how I miss Saturday morning cartoons. This will have to do.



What does Stephen Meyer really think?

One of the most frustrating things about the current crop of Intelligent Design Creationists is that it's impossible to pin them down on what they really think happened in the history of life. We know that some of them are closet Young Earth Creationists so we can guess what they think. They may be arguing that bacterial flagella reveal the actions of a designer but they actually don't believe any of the data used to make that argument. They think that all species (or kinds) were created at once just a few thousand years ago.

Other Intelligent Design Creationists seem to believe in a different form of creation but who knows what it is? Take Stephen Mayer, for example, you can read his books from cover to cover and still not know what he thinks about the history of life. It's clear that the Cambrian Explosion is a big deal for him and it's clear that he thinks god is behind it all but he's remarkably noncommittal about what actually happened according to his interpretation of the evidence.

Friday, November 06, 2015

The cost of a new gene

Let's think about the biochemical cost associated with adding some new piece of DNA to an existing genome. Michael Lynch has been thinking about this for a long time. He notes that there certainly IS a cost (burden) because the new bit of DNA has to be replicated. That means extra nucleotides have to be synthesized and polymerized every time a cell replicates.

This burden might seem prohibitive for strict adaptationists1 since everything that's detrimental should be lost by negative selection. Lynch, and others, ague that the cost is usually quite small and if it's small enough the detrimental effect might be below the threshold that selection can detect. When this happens, new stretches of DNA become effectively neutral (nearly neutral) and they can be fixed in the genome by random genetic drift.

The key parameter is the size of the population since the power of selection increases as the population size increases. Populations with large numbers of individuals (e.g. more than one million) can respond to the small costs/burdens and eliminate excess DNA whereas populations with smaller numbers of individuals cannot.

Canada's new Minister of Science, Kirsty Duncan, is NOT a Nobel Prize winner

Canada has a new government under the Liberal Party and a new Prime Minister, Justin Trudeau. I'm very excited about this change. I'm a member of the Liberal Party of Canada and I voted for the Liberal Candidate in my riding.

One of the big changes is supposed to be increased transparency of government, more openness with the press, and a promise to base decisions on evidence and science. In other words, truth is supposed to be the new buzzword on Parliament Hill. Trudeau's new cabinet even has a Minister of Science, unlike previous cabinets.

Wednesday, November 04, 2015

Justin Trudeau and his new cabinet

This is our new Canadian Prime Minister walking to Rideau Hall with his new cabinet ministers for the swearing in ceremony where he officially takes over the government. It's very exciting. No Prime Minister has ever done this before today.



Was Jesus a real person? - see what denialism looks like

Jerry Coyne wrote up something about the historical Jesus where he suggested that there wasn't much evidence for his existence: BBC poll: 40% of Brits don’t believe that “Jesus was a real person,” but BBC assumes he was!].

Here's what Jerry said,
Now I may be wrong, but the more I read this, the more I think that reader Ant was right in his interpretation. What’s more galling is that the BBC is taking what “many scholars believe” as the gospel truth—pardon the pun—despite the fact that close scrutiny gives virtually no extra-Biblical evidence for a historical Jesus. I’m still convinced that the judgement of scholars that “Jesus was a real man” comes not from evidence, but from their conviction that the Bible simply couldn’t be untruthful about that issue. But of course we know of cases where myths grew up that weren’t at bottom derived from a historical individual.
There's nothing particularly wrong with what Jerry says. As far as I know the evidence that Jesus actually existed is not strong and, even more importantly, there's no independent evidence that he rose from the dead or performed miracles.

Tuesday, November 03, 2015

We are all Irish according to Ancestry.com

One of my wife's relatives just had her DNA tested by Ancestry.com and the results show that she is 61% Irish.1 She was (pleasantly) surprised so she shared the information with her relatives, including Ms. Sandwalk.

I was also surprised because I have a pretty extensive genealogy of my wife's side of the family and there's no ancestor from Ireland. Her grandparents—the aunt's parents—have typically Scottish surnames and they are the product of several generations of Scottish ancestors from a small community in Eastern Ontario.

I know of all the ancestors of the aunt (and my wife's mother) for five generations. That's 32 ancestors—their great-great-great-grandparents (Ms. Sandwalk's great4-grandparents). There were four ancestors born in England and 28 born in Scotland, mostly around Glasgow. The original settlers of this district all came from Scotland. That means that to a first approximation about 87% of the aunt's DNA comes from Scotland.

Methodological naturalism at Dover

I'm one of those scientists who don't think that science as a way of knowing is restricted to investigating natural causes [John Wilkins Revisits Methodological Naturalism ]. I think that science can easily investigate supernatural claims and show that they are wrong. In theory, science might even show that the supernatural exists. Some (most?) philosophers agree. Maarten Boudry is the best known [Is Science Restricted to Methodologial Naturalism?].

This year is the tenth anniversary of Kitzmiller v. Dover Area School District. At that trial, the plaintiffs successfully convinced Judge Jones that intelligent design isn't a science because it invokes supernatural causes. The expert witnesses testified that, by definition, science is limited by methodological naturalism. I disagree with the expert witnesses at the trial and I agree with many leading philosophers that science is not restricted to methodological naturalism [Can Science Test Supernatural Worldviews? ].

Molecular evidence supports the evolution of the major animal phyla

For those of you who are interested in the evolution of the major animal phyla, let me introduce you to the topic.

See the little red circle on the phylogenetic tree on the right? That's what we're talking about.

Most of the major animal phyla are first observed as primitive fossils in the Cambrian about 540 million years ago. The fossils cluster around dates that only span a few million years (about 10 million years). This is the Cambrian Explosion (see little red circle).

There's considerable debate among evolutionary biologists about what caused this relatively rapid appearance of diverse and disparate large fossils. Intelligent Design Creationist, Stephen Meyer decided that such a debate casts serious doubt on evolution as an explanation for the history of life so he wrote a book called Darwin's Doubt.

Monday, November 02, 2015

Why does Evolution News & Views not allow comments?

The Discovery Institute blog, Evolution News & View (sic) doesn't allow comments. They're beginning to feel a bit guilty about that so there have recently been two posts on the topic.

David Klinghoffer says: Why No Comments at Evolution News?

Michael Egnor writes: Comments by Darwinists: Another Perspective

The problem from their perspective is that their opponents are rude, crude, and abusive so they have to ban all comments. Here's how David Klinghoffer puts it.
So what are we supposed to do when, under a free-for-all commenting policy, Darwinists like Moran -- who is far from scraping the bottom of the barrel as far as online evolutionists go -- post abusive, defamatory, and false comments on our own news site? Should we delete their comments? Edit them? But then we would be accused of "censorship."

Should we perhaps allow them to say whatever they like, fouling the carpet in our own living room? When they have every opportunity to write what they like where they like and receive an answer from us, if the challenge rises to the level of being worthy of a reply? Why in the world would we do that?

If we can't accept providing a free forum for a great deal of nasty, false, and vacuous chatter, the only alternative is to devote significant time to moderating the forum, policing the sandbox, and then defending that moderation at every step as it is challenged. That would require staffing that we can't afford.
The problem with that line of reasoning is that there already is an ID blog that allows comments. Check out Uncommon Descent to see who's fouling the carpet.

What they're really worried about isn't the "Darwinists." It's Mung, bornagain, Vy, Andre, Virgil Cain, Upright BiPed, Mapou and others like them who will dominate the comments section and give the Discovery Institute a bad reputation.


Evolution as a foundational concept in biochemistry and molecular biology

The American Society for Biochemistry and Molecular Biology (ASBMB) has been promoting a new way of teaching undergraduate courses. The idea is to concentrate on fundamental principles and concepts rather than on trivial details. The various working groups came up with a list of these fundamental concepts under five main headings: Evolution; Matter and Energy Transformation; Homeostasis; Macromolecular Structure & Function; and Biological Information.

I've discussed the concepts before [ASBMB Core Concepts]. There are problems.

Various committees continue to meet in order to build a "concept inventory" to guide the new curriculum. There have been a series of workshops organized around the main themes. The participants in the workshops are, for the most part, teachers at small universities and colleges. They have lots of experience teaching undergraduate courses but they aren't necessarily experts in the subject material.

I saw this clearly when I attended a session at the last Experimental Biology meeting in Boston last April. The purpose of the meeting was to review the major concepts in Evolution and Homeostasis. I met a great deal of resistance from the workshop leaders when I tried to explain the concepts of neutral alleles and random genetic drift and show them why they were so important when comparing sequences and constructing phylogenetic trees.
INTEGRATING EVOLUTION AND HOMEOSTASIS WITH THE CORE CONCEPTS OF BIOCHEMISTRY AND MOLECULAR BIOLOGY
Symposium Tues. 9:45 am Boston Convention & Exhibition Center, room 256

Chaired: E. Bell

9:45 RCN-UBE: Integrating Evolution and Homeostasis with the Core Concepts of Biochemistry and Molecular Biology J.E. Bell, A. Aguanno, P. Mertz, M. Johnson and K.M. Fox. Univ. of Richmond, Union Col., NY, Univ. of Alabama, St Mary’s Col. of Maryland and Marymount Manhattan. (559.2)

Presenters:
Small Group Work: Integrating Evolution and Homeostasis into the Core Concepts E. Bell, Univ. of Richmond A. Aguanno, Marymount Manhattan Col.

Group Discussion on Core Concept integration with Homeostasis A. Aguanno, Marymount Manhattan Col.

Small Group Work: Question Development Involving Evolution and Homeostasis M. Johnson, Univ. of Alabama

Group Presentations and Discussion on Question Implementation K. Fox. Union Col.
This same group has published some of their findings in the July/August issue of the education journal, Biochemistry and Molecular Biology Education (BAMBED)1 (Aguanno et al. 2015).

Here are the learning objectives they have developed under the "Evolution" concept.
  • central importance of the theory of evolution
  • Darwin's theory of evolution
  • process of natural selection
  • evidence for the theory of evolution
  • molecular basis of natural selection
I really think this misses the boat in a biochemistry context where molecular evolution plays such an important role. It will be hard to discuss genome organization and junk DNA, for example, if students don't know about population genetics and random genetic drift. It will be hard to explain (correctly) why different proteins in different species have different amino acid sequences if students don't know about neutral alleles.

I pointed this out to the authors at the meeting and stimulated a discussion about these concepts. The authors, and the other teachers in the room, were pretty certain that the differences in amino acid sequences were all due to natural selection. Most of them had never heard of random genetic drift.

The problem here is that the learning objectives and the "capstone experiences" are being developed by teachers who don't really understand evolution. It is assumed that the best people to work on the new curriculum are experienced teachers but that's demonstrably false. (It applies to the other concepts as well.)

It turns out that biochemistry professors are not as knowledgeable about core concepts as you might imagine.

The authors surveyed 161 teachers in 143 institutions across the USA to find out what are the most important concepts in a biochemistry and//or molecular biology course.

The results, right, indicate that less than 8% of the respondents thought that evolution was an important concept.

This could be due, in part, to the fact that biochemistry courses are often taught by professors who are members of a chemistry department but no matter what the explanation it looks like we have a lot of work ahead of us if we are going to convince our colleagues to make evolution a core concept.

I'm pretty sure that many of the people who teach our introductory biochemistry courses at the University of Toronto don't see evolution as a core concept and don't understand modern evolutionary theory.


1. Disclaimer: I am on the editorial board of that journal.

Aguanno, A., Mertz, P., Martin, D., and Bell, E. (2015) A National Comparison of Biochemistry and Molecular Biology Capstone Experiences. BAMBED 43:223-232. [doi: 10.1002/bmb.20869]

The birth and death of salmon genes

Modern Salmonidae (salmon and its relatives) have genomes that show clear evidence of an ancient duplication event. Berthelot et al. (2014) sequenced the rainbow trout genome and constructed a phylogenetic tree of all teleost fish. The genome duplication event in the Salmonidae lineage can be dated to approximately 96 million years ago (96 ± 5.5 Mya).

This event provides an opportunity to track the fate of the duplicated protein-coding genes. How many of the original duplicates are left and what happened to them?

There were able to get reliable data on 9,040 of the original genes in the ancestral genome. (That's about one third of the estimated 31,000 genes in the genome of the original species.) Of those 9,040 genes, 4,728 (52%) are now single copy genes because one of the duplicated genes has been lost. Many of these original genes are still detectable as pseudogenes at the right position in the genome.

By combining these results with studies of more ancient genome duplications in the vertebrate lineage, it looks like the average rate of gene loss is about 170 genes per million years (Berthelot et al., 2004). It's likely that in the majority of cases one of the duplicates will eventually become inactivated by mutation and that allele will become fixed in the genome by random genetic drift. (Some early inactivation events may be selected.)

4,312 (42%) of the original duplications have been retained in the trout genome as a small family consisting of two paralogues. In some cases the two paralogues have diverged and in some cases they are expressed in different tissues or at different stages of development. This suggests that the two copies have evolved different functions.

However, most of the duplicated genes seem to be performing similar functions and it's likely that there is no selective pressure to retain two copies. There just hasn't been enough time to inactivate one copy.

The trout genome contains 241 ancient microRNA genes and 233 of them still have two copies, one from each of the duplicated genomes. The authors suggest that this is significant and it indicates that multiple copies on these microRNA genes are needed. I'm not sure if this is true since these genes are quite a bit smaller than the average protein-coding gene so they will take longer to inactivate by mutation.

In any case, the big picture provides us with lots of data on the birth of new genes by duplication and death of genes by pseudogene formation.


Berthelot, C., Brunet, F., Chalopin, D., Juanchich, A., Bernard, M., Noël, B., Bento, P., Da Silva, C., Labadie, K., and Alberti, A. (2014) The rainbow trout genome provides novel insights into evolution after whole-genome duplication in vertebrates. Nature communications, 5:3657 April 22, 2014 [doi:10.1038/ncomms4657]

Sunday, November 01, 2015

Florabama speaks

I've been trying to argue a few points on the creationist blogs but I have to admit that I'm not making any progress at all. Even the simplest, most obvious, points are vigorously contested by the ID crowd over there.

My latest attempt was on the post, Suzan Mazur’s Paradigm Shifters is now available from Amazon, where I tried to explain that Denyse O'Leary's version of Darwinism is not the best description of evolutionary theory and that many of Suzan Mazur's "Paradigm Shifters" have missed the revolution that occurred in the late 1960s.

Didn't work.

Now someone named "Florabama" has posted a comment that illustrates the problem we're up against. I thought I'd share it with Sandwalk readers. It may not be possible to teach such a person anything about science.

More stupid hype about lncRNAs

I've just posted an article about a group of scientists at UCLA who claimed to have discovered 3,000 new genes in the human genome [3,000 new genes discovered in the human genome - dark matter revealed].

They did no such thing. What they discovered was about 3,000 previously unidentified transcripts expressed at very low levels in human B cells and T cells. They declared that these low-level transcripts are lncRNAs and they assumed that the complementary DNA sequences were genes. Their actual result identifies 3,000 bits of the genome that may or may not turn out to be genes. They are PUTATIVE genes.

None of that deterred Karen Ring who blogs at The Stem Cellar: The Official Blog of CIRM, California's Stem Cell Agency. Her post on this subject [UCLA Scientists Find 3000 New Genes in “Junk DNA” of Immune Stem Cells] begins with ...

3,000 new genes discovered in the human genome - dark matter revealed

Let's look a a recent paper published by a large group of medical researchers at the University of California, Los Angeles (USA). The paper was published online a few days ago (Oct. 26, 2015) in Nature Immunology.

The authors clam to have discoverd 3,000 previously unknown genes in the human genome.

The complete reference is ...

Saturday, October 24, 2015

Intelligent design needs to clean up its act if it expects to be taken seriously

Jonathan McLatchie tried to make the case that ID is different from creationism in two recent videos on a Christian apologetics podcast [see Jonathan McLatchie says that intelligent design is a science and Jonathan McLatchie explains the difference between intelligent design and creationism].

I think there's some serious attempts to do science among ID proponents but I also think it's bad science. It's fun, informative, and challenging to debate real science with knowledgeable, informed members of the ID community.

However, that same community embraces many, many advocates who are not knowledgeable about evolution and not informed about how science works. They are not scientists by any stretch of the imagination but they pretend to be scientific. Many of them are Young Earth Creationists who seriously think that the universe was created pretty much as it is only 6000 years ago. While it's true that every ID proponent is a creationist (i.e believes in the existence of a supernatural creator) there are some versions of creationism that are more irrational than others.

The theistic evolution version of creationism rejects the views of their anti-science YEC friends but Intelligent Design Creationism embraces all comers as long as they are vehemently opposed to materialism and evolution. That's fine, but then ID can't claim to be scientific. You can't have your cake and eat it too. Either you try to act like scientists, in which case you have to oppose the kooks and YECs in your movement, or you admit that you are a religious and social movement, in which case you stop pretending to be a science.

I hope that the knowledgeable, informed, members of the ID community will abandon the ridiculous path they've taken where they try to make a scientific case for ID knowing full well that the majority of their supporters disagree strongly with their premises (e.g. common descent). That's an untenable position.

We've seen recently that some ID proponents are attempting to do this. I'm thinking of Jonathan McLatchie and Vincent Torley right now but there are others. How is it working out? Look at the Torley post on Uncommon Descent where he's trying to explain evolution to IDiots: Human and chimp DNA: They really are about 98% similar. It's an uphill battle. The kooks are accusing him of becoming a Darwinist.

But that's exactly what the ID community needs to do in order to gain credibility. They need to shed the kooks and the IDiots who make them look silly. When they do that, they may find that more of us are willing to have a serious discussion about science.

David Klinghoffer is one of the names I mentioned in an earlier post when I identified leading ID proponents who have no clue about the science they are opposing. Others are Denyse O'Leary, Barry Arrington, Phillip Johnson, Casey Luskin,1 David Klinghoffer, Paul Nelson, John West, and William Lane Craig. These people represent the face of the ID movement and that's how we're going to judge Intelligent Design Creationism unless they clean up their act. (We also judge it by the people who post comments on blogs and Facebook and by those politicians who support it in the public sphere.)

Klinghoffer posts on Evolution News & Views (sic)—a site that doesn't allow comments. His latest post is a classic example of the problems that the ID movement faces: Here's Why We Answer Some of Our Less Cogent Critics.

As you can see, he avoids the issue I raised in favor of an ad hominem attack. Wouldn't it be nice to see a scientific debate between Michael Behe and David Klinghoffer on the meaning of evolution? Not going to happen as long as ID is primarily a religious movement.


1. Casey Luskin can't decide how old the universe is but he leans toward Young Earth Creationism. Yet he's a leading spokesman for the "science" of intelligent design.

Friday, October 23, 2015

Nature publishes a misleading history of the discovery of DNA repair

The history of DNA repair is well-known. Here's a quote from "Early days of DNA repair: discovery of nucleotide excision repair and homology-dependent recombinational repair" by W.D. Rupp in 2013 (Rupp, 2013).
This article describes events related to the first papers published in the 1960s describing nucleotide excision repair (NER) and homology-dependent recombinational repair.
Here's are the relevant papers.
Setlow, R.B., and Carrier, W.L. (1964) The disappearance of thymine dimers from DNA: An error-correcting mechanism. Proc. Natl. Acad. Sci. (USA) 51:226–231. [Full Text]

Boyce, R.P., Howard-Flanders, P. (1964) Release of ultraviolet light-induced thymine dimers from DNA in E. coli K-12. Proc. Natl. Acad. Sci. (USA) 51:293–300. [Full Text]

Pettijohn, D, and Hanawalt, P. (1964) Evidence for repair-replication of ultraviolet damaged DNA in bacteria. J. Mol. Biol. 9:395–410. [PubMed]

Thursday, October 22, 2015

Jonathan McLatchie says that intelligent design is a science

Here's another short podcast on a Christian apologetics show. Jonathan McLatchie is being asked whether intelligent design is a science.


Café Scientifique in Mississauga

Some of you might recall that I gave a presentation at a Café Scientifique in Mississauga (Ontario, Canada) [Café Scientifique]. It was a lot of fun and there were many interesting people at the meeting.

The new season continues on Monday, October 26h with a meeting at 7 pm at The Franklin House, 263 Queen St S., in Streetsville, Mississauga (Ontario Canada) [see Meetup]. Come and join us for a discussion about teaching critical thinking in Ontario schools. My friend Chris DiCarlo is the speaker.

Come hear TVO 2008 Best Lecturer winner Christopher DiCarlo talk about “Introducing Standard Critical Thinking Skills to Ontario High Schools”.

The topic follows Dr. DiCarlo's efforts over the last five years or so to personally lobby the Ministry of Education and various School Boards in an effort to start a pilot project which introduces both teachers and students to the value of basic Critical Thinking skills. The Pilot Project began in September, 2014 with the Upper Grand District School Board. The first year of the project was a great success. It is now entering its 2nd phase which involves the development of video footage and written materials for Learning Modules which will be made available to all teachers throughout Ontario and eventually, Canada. These modules can be used for any grades, though they are intended for grades 9 and 10 in order to introduce these skills as early as possible in High School. The eventual plan also includes the development of a stand-alone course for Grade 12.

Dr. Christopher DiCarlo is a philosopher, educator, and author. He currently teaches in the Faculties of Philosophy at the University of Toronto and Ryerson University. He is also a lifetime member of Humanist Canada and an Expert Advisor for the Centre for Inquiry Canada.

He has been invited to speak at numerous national and international conferences and written many scholarly papers ranging from bioethics to cognitive evolution. His latest book entitled: How to Become a Really Good Pain in the Ass: A Critical Thinker’s Guide to Asking the Right Questions was released worldwide by Prometheus Press in August, 2011 and is currently in its fifth printing and is a best-seller in the U.S.

He is currently working on his latest book tentatively entitled: Flying Without A Pilot: A Determined Look at the Future of Ethics, Law, and the Value of Human Behavior.

In April, 2008 he was awarded TV Ontario’s Big Ideas Best Lecturer in Ontario Award for his lecture “The Relations of Natural Systems”.

In August, 2008, he was honoured with the Canadian Humanist of the Year Award from the Humanist Association of Canada.

Dr. DiCarlo is the Director of Critical Thinking Solutions, a consulting business for individuals, corporations, and not-for-profits in both the private and public sectors. He is also the developer of the first Pilot Project in Canada to introduce Standardized Critical Thinking skills into the Ontario Public High School curriculum which has begun in the Upper Grand District School Board.


Wednesday, October 21, 2015

The quality of the modern scientific literature leaves much to be desired

Lately I've been reading a lot of papers on genomes and I've discovered some really exceptional papers that discuss the existing scientific literature and put their studies in proper context. Unfortunately, these are the exceptions, not the rule.

I've discovered many more authors who seem to be ignorant of the scientific literature and far too willing to rely of the opinions of others instead of investigating for themselves. Many of these authors seem to be completely unaware of controversy and debate in the fields they are writing about. They act, and write, as if there was only one point of view worth considering, theirs.

How does this happen? It seems to me that it can only happen if they find themselves in an environment where skepticism and critical thinking are suppressed. Otherwise, how do you explain the way they write their papers? Are there no colleagues, post-docs, or graduate students who looked at the manuscript and pointed out the problems? Are there no referees who raised questions?

Tuesday, October 20, 2015

Jonathan McLatchie explains irreducible complexity

Listen to Jonathan McLatchie's explanation of irreducible complexity and why it represents a problem for the "neo-Darwinian paradigm." Keep in mind that he has been asked to do this by a Christian pastor on an Christian apologetics podcast. I wonder why?

McLatchie claims that an irreducibly complex system consist of a number of subfunctions where the removal of one subfunction renders the whole system nonfunctional. He implies that such systems can't be explained by evolution. Do all ID proponents agree? If we can show you a reasonable evolutionary explanation of the evolution of a single irreducibly complex system, using McLatchie's definition, would that refute his claim that such systems present a challenge to evolution? How about if we show you two examples? Three?



Vincent Torley and the genetic fallacy

Vincent Torley didn't like my post on Jonathan McLatchie's defense of ID [Jonathan McLatchie explains the difference between intelligent design and creationism]. Torley says that I have committed the sin of genetic fallacy [Larry Moran commits the genetic fallacy].

How terrible! Let's see if I can fix the problem.

To start, Vincent Torley says,
Because science is defined by its methodology, any attempt to discredit a field such as Intelligent Design by casting aspersions on the motives of its leading practitioners completely misses the point. No matter what their motives might be, the only question which is germane in this context is: do Intelligent Design researchers follow a proper scientific methodology, and do ID proponents support their arguments by appealing to that methodology? The answer to this question should be obvious to anyone who has read works such as Darwin’s Black Box, The Edge of Evolution, Signature in the Cell and Darwin’s Doubt. Intelligent Design researchers and advocates commonly appeal to empirical probabilities (which can be measured in the laboratory), mathematical calculations (about what chance and/or necessity can accomplish), and abductive reasoning about historical events (such as the Cambrian explosion) which bear the hallmarks of design.

Jonathan McLatchie explains the difference between intelligent design and creationism

This is a video from One Minute Apologist. Really, I'm not kidding. There actually is a man called Bobby Conway who is the One Minute Apologist.

He became a devout Christian when he was 19 and subsequently went off to Bible school then got a Doctorate of Ministry in Apologetics from Southern Evangelical Seminary. He's now a Ph.D. candidate in the Philosophy of Religion department at the University of Birmingham (UK). I'd love to be on his thesis committee but I'm not a philosopher. Maybe they'll invite John Wilkins to serve as external reviewer at the thesis defense?

The theme of his videos and website is ...
We provide quick, credible answers to apologetic questions that resource people with a hunger to defend their Christian faith.

Here's an interview with Jonathan McLatchie where McLatchie tires to pretend that ID is a legitimate scientific investigation that has nothing to do with creationism. Keep in mind that he's doing this while being interviewed by a Christian Pastor in a Christian apologetics video. Watch the video, it's only one minute.


Monday, October 19, 2015

Election Day in Canada: seat projections

The CBC poll-tracker website shows the Liberal Party in the lead with 37% of the vote. The Conservative Party is polling at 31% and the New Democratic Party trails at 22%.

In close elections it is extremely difficult to project those numbers into seats because there are many close races and the number of people sampled in each riding is quite small. Nevertheless, ThreeHundredEight and CBC have been making seat projections since the campaign began.

Here's the latest seat projections as of yesterday ...


If these projections are accurate then the Liberals will win the most seats but will be far short of a majority. Justin Trudeau will become the next Prime Minister of Canada and Stephen Harper will be gone.

The main uncertainty is voter turnout. A lot of Liberal voters are uncertain about who to vote for and many of them will be first-time voters, if they vote. The Conservative vote, on the other hand, is pretty solid and Conservative voters are very likely to vote today. Most of the Conservative vote is concentrated in rural ridings that are guaranteed wins for the Conservatives. It is still possible for the Conservatives to win enough close races to finish on top with the most seats.1

The NDP vote is soft and dropping. The biggest change in the past few days is the seat projections in Quebec where the NDP won 59 seats in the last election. (A big surprise.) As of today, CBC is projecting that they will only win 34 seats. All three of the other parties are projected to gain seats but the Liberals gain the most. The battle in Ontario was reduced several weeks ago to mainly a fight between Liberals and Conservatives. (There are a few ridings where the Liberals and NDP are neck-and-neck.)

It's interesting that the three-way race in British Columbia hasn't changed very much in a long time. The latest projections have the Conservatives slightly ahead with 16 seats to 13 for the Liberals and 12 for the NDP. (Plus one seat for the Green Party.) There are several scenarios where the overall winner will be decided by the vote in British Columbia. It could be a long night.

The result in the Greater Toronto Area (GTA) was decided weeks ago. The Liberals are going to capture almost all of the seats. The only secure victory for the Conservatives is Thornhill, and the only projected victory for the NDP is Toronto-Danforth. [See the interactive map at: ThreeHundredEight.] Olivia Chou is trailing badly in Spadina-Fort York.

In my area, Mississauga-Brampton, every seat is projected to go Liberal and many Conservative MPs are going down to defeat, including my own MP Bob Dechert. The NDP is not a factor in any of these ridings.


1. This does not mean that Harper will be able to hold on to power but it makes things complicated.

Election Day in Canada: popular vote predictions

The CBC poll-tracker website tracks a number of public opinion polls and calculates a weighted average. The latest numbers have the Liberal Party winning the most votes with the Conservative Party (current government) in second place.


This is a close election so normally you would have to take these numbers with a large grain of salt but the trend over the past month is pretty obvious.


There has been a steady decline in support for the New Democratic Party (NDP) and a steady increase in Liberal support. The percentage of people who say they will vote Conservative has not changed much. It would be truly astonishing if the actual results tonight are much different than the poll results in terms of total votes. (There could be a total collapse of the NDP vote but not a reversal of fortune.)


Friday, October 16, 2015

Human mutation rates

I was excited when I saw the cover of the Sept. 25th (2015) issue of Science because I'm very interested in human mutation rates. I figured there would have to be an article that discussed current views on the number of new mutations per generation even though I was certain that the focus would be on the medical relevance of mutations. I was right. There was one article that discussed germline mutations and the overall mutation rate.

The article by Shendure and Akay (2015) is the only one that addresses human mutation rates in any meaningful way. They begin their review with ...
Despite the exquisite molecular mechanisms that have evolved to replicate and repair DNA with high fidelity, mutations happen. Each human is estimated to carry on average ~60 de novo point mutations (with considerable variability among individuals) that arose in the germline of their parents (1–4). Consequently, across all seven billion humans, about 1011 germline mutations—well in excess of the number of nucleotides in the human genome—occurred in just the last generation (5). Furthermore, the number of somatic mutations that arise during development and throughout the lifetime of each individual human is potentially staggering, with proliferative tissues such as the intestinal epithelium expected to harbor a mutation at nearly every genomic site in at least one cell by the time an individual reaches the age of 60 (6).

Wednesday, October 14, 2015

"#For the King" nears the end of its Kickstarter campaign - add a Darwin statue!

My son's new game, For The King (#ForTheKing), is doing well on Kickstarter. So far they have over 3000 backers and over $120,000 [Kickstarter: For The King]. They met their launch goal within 24 hours and now they're closing in on the last defined stretch goal at $125,000 (balloons and highlands).

There's less than two days to go and the team [IronOak Games] has provided some incentive. Every time you post or tweet about For The King using the #ForTheKing hashtag your name will be put in a draw and the winning name will get a statue of him/her in the game.

If my name is chosen I'm going to ask for a statue of Charles Darwin. Help me get a stature of Darwin into the game by tweeting and posting #ForTheKing and promising to substitute Darwin for your own statue if you win.



Friday, October 09, 2015

Brace yourselves, a new "Icons" is coming

Having narrowly escaped one catastrophe—the end of the world on October 7th—there's another looming on the horizon. Denyse O'Leary tells us that Jonathan Wells is preparing an "update" of his book Icons of Evolution [What’s happened since Icons of Evolution (2002)?].

You know what's going to happen next year if she is right? We are going to deluged with pre-publication publicity promoting the book that we can't see. We'll be told that it refutes evolution and builds on the outstanding success of the first book. We'll be told that Jonathan Wells addresses and refutes all of the criticisms of his first book and adds some more devastating proofs that the Rev. Sun Myung Moon is right.

None of this will be true, of course, but that's why the IDiots will get in their licks before we can prove it by reading the book. This is the standard ploy taken by the Discovery Institute over the past few years.

I know a lot about Icons of Evolution because for seven years it was required reading in my course on critical thinking. All my students had to write essays on one of the chapters. They had to analyze the arguments that Wells was making and decide whether they were valid or not.

Some of you may have forgotten about Icons of Evolution so you may have to refresh your memory by reading the short summary and reviews on the Wikipedia site [Icons of Evolution]. You can see that Wells has his work cut out for him if he's going to reply to all of the criticism.

Here's a few posts that I have done over the years to show that Icons of Evolution is seriously flawed. Some of them show that Jonathan Wells is dishonest—something that my students usually discovered on their own.1
I'm hoping to get a response in his new book but I'm not holding my breath. I spent a lot of time showing that his last book, The Myth of Junk DNA was flawed but here's how Jonathan Wells responded [see Jonathan Wells Sends His Regrets] ...
Oh, one last thing: “paulmc” referred to an online review of my book by University of Toronto professor Larry Moran—a review that “paulmc” called both extensive and thorough. Well, saturation bombing is extensive and thorough, too. Although “paulmc” admitted to not having read more than the Preface to The Myth of Junk DNA, I have read Mr. Moran’s review, which is so driven by confused thinking and malicious misrepresentations of my work—not to mention personal insults—that addressing it would be like trying to reason with a lynch mob.
Denyse O'Leary warns us that there may be more "icons" in the next book. She quotes someone named Stephen Batzer who claims that there are three new "show stoppers."
  1. That Darwin’s finches are simply races of the same bird. There has been no speciation.
  2. That the tree of life is not viable. “It’s a bush!” they respond. Well, then Darwin was wrong, and the model is wrong. If it’s a *bush* it isn’t a *tree*. The Darwinian model is common descent and gradual differentiation. That has been shown to be false, because of #3.
  3. ORFAN (Orphan) genes. Where do novel genes come from? If common genes mean common descent, then novel genes mean intervention and an innovator.
I wish I were still teaching my course. These are so easy to refute that all my students would have gotten A's on their essays. It shows you that the level of biology expected by Denyse O'Leary and the IDiots is nowhere near as elevated as second year university.


1. Every year I would have students setting up an appointment to see me in my office to discuss a problem they were having with their essay. They had discovered that some things in Icons seemed inconsistent with the truth and they wondered where they were going wrong.

Wednesday, October 07, 2015

Nobel Prize for DNA repair

Tomas Lindahl, Paul Modrich, and Aziz Sancar shared the 2015 Nobel Prize in Chemistry for "for mechanistic studies of DNA repair" [Nobel Prize, Chemistry 2015].

Here's some of the press release.
In the early 1970s, scientists believed that DNA was an extremely stable molecule, but Tomas Lindahl demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible. This insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA.

Aziz Sancar has mapped nucleotide excision repair, the mechanism that cells use to repair UV damage to DNA. People born with defects in this repair system will develop skin cancer if they are exposed to sunlight. The cell also utilises nucleotide excision repair to correct defects caused by mutagenic substances, among other things.

Paul Modrich has demonstrated how the cell corrects errors that occur when DNA is replicated during cell division. This mechanism, mismatch repair, reduces the error frequency during DNA replication by about a thousandfold. Congenital defects in mismatch repair are known, for example, to cause a hereditary variant of colon cancer.
What about Phil Hanawalt?

Meanwhile, in other news: Discovery and Characterization of DNA Excision Repair Pathways: the Work of Philip Courtland Hanawalt ...
In 1963, Hanawalt and his first graduate student, David Pettijohn, observed an unusual density distribution of newly synthesized DNA during labeling with 5-bromouracil in UV-irradiated E. coli. These studies, along with the discovery of CPD excision by the Setlow and Paul Howard-Flanders groups, represented the co-discovery of nucleotide excision repair.
And Wikipedia [Philip Hanawalt] says,
Philip C. Hanawalt (born in Akron, Ohio in 1931) is an American biologist who discovered the process of repair replication of damaged DNA in 1963. He is also considered the co-discoverer of the ubiquitous process of DNA excision repair along with his mentor, Richard Setlow, and Paul Howard-Flanders. He holds the Dr. Morris Herzstein Professorship in the Department of Biology at Stanford University,[1] with a joint appointment in the Dermatology Department in Stanford University School of Medicine.
Here's what Hanawalt himself says about discovering DNA excision repair [The Awakening of DNA Repair at Yale] ...
Upon joining the faculty at Stanford University in late 1961 as Research Biophysicist and Lecturer, I returned to the problem of what UV did to DNA replication, now that we knew the principal photoproducts. I wanted to understand the behavior of replication forks upon encountering pyrimidine dimers, and I was hoping to catch a blocked replication fork at a dimer. Using density labeling with 5-bromouracil and radioactive labeling of newly-synthesized DNA, we were able to observe partially replicated DNA fragments in E. coli [13]. However, in samples from UV irradiated bacterial cultures, the density patterns of nascent DNA indicated that much of the observed synthesis was in very short stretches, too short to appreciably shift the density of the DNA fragments containing them [14]. I communicated these results to Setlow by phone and learned that he had just discovered that pyrimidine dimers in wild type cells, but not in Ruth Hill’s UV sensitive mutant, were released from the DNA into an acid soluble fraction. We speculated in discussion that my student, David Pettijohn, and I were detecting a patching step by which a process of repair replication might use the complementary DNA strand as template to fill the single-strand gaps remaining after the pyrimidine dimers had been removed. At about the same time, Paul Howard-Flanders in the Department of Therapeutic Radiology at Yale had isolated a number of UV-sensitive mutants from E. coli K12 strains, and he was able to show that these mutants were also deficient in removing pyrimidine dimers from their DNA. The seminal discovery of dimer excision was published by the Setlow and Howard-Flanders groups, as the first indication of an excision repair pathway [15,16]. Of course, the excision per se is not a repair event but only the first step, since it generates another lesion, the gap in one strand of the DNA. We carried out more controls, to then claim that we had discovered a non-conservative mode of repair replication, constituting the presumed patching step in the postulated excision-repair pathway [17]. I later showed that DNA containing the repair patches could undergo semiconservative replication with no remaining blockage [18].

Richard Boyce and Howard-Flanders at Yale also documented excision of lesions induced by mitomycin C in E. coli K12 strains, indicating some versatility of excision repair [19]. In a collaboration with Robert Haynes, I found a similar pattern of repair replication after nitrogen mustard exposure to that following UV, and we concluded that “it is not the precise nature of the base damage that is recognized, but rather some associated secondary structural alteration …” We speculated that “[s]uch a mechanism might even be able to detect accidental mispairing of bases after normal replication,” thus predicting the existence of a mismatch repair pathway [20]. Mismatch repair was reported by Wagner and Meselson a decade later [21] and yet another excision repair mode, termed base excision repair, was discovered by Tomas Lindahl [22].
One of Hanawalt's students was Jonathan Eisen [Tree of Life]. I'll be interested in hearing what he has to say about this Nobel Prize. It seems unfair to me.


Ten years after Dover - an excellent decade for Intelligent Design Creationism?

This month marks the tenth anniversary of the Kitzmiller v. Dover case in Pennsylvania [Tammy Kitzmiller, et al. v. Dover Area School District, et al.]. The legal victory will be celebrated by NCSE and Panda's Thumb and by many other supporters of science and evolution. If American law is your thing, then please join in the celebration of a legal victory.

It's much more interesting to evaluate whether the legal victory in Pennsylvania had any significant effect on the general public. Did it cause people to change their minds and abandon Intelligent Design Creationism to embrace science? Has America moved closer to the time when real science can be taught in the schools without interference from religion? Have politicians stopped trying to water down evolution in the public schools because of Judge Jones' decision in Kitzmiller v Dover? Have politicians stopped opposing evolution and has the public stopped voting for those who do?