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Thursday, September 18, 2008

Richard Dawkins on the Michael Reiss Affair

 
Here's a letter that Richard Dawkins sent to New Scientist [Letter: Richard Dawkins on the Royal Society row
The Reverend Michael Reiss, the Royal Society's Director of Education, is in trouble because of his views on the teaching of creationism.

Although I disagree with him, what he actually said at the British Association is not obviously silly like creationism itself, nor is it a self-evidently inappropriate stance for the Royal Society to take.

Scientists divide into two camps over this issue: the accommodationists, who 'respect' creationists while disagreeing with them; and the rest of us, who see no reason to respect ignorance or stupidity.

The accommodationists include such godless luminaries as Eugenie Scott, whose National Center for Science Education is doing splendid work in fighting the creationist wingnuts in America. She and her fellow accommodationists bend over backwards to woo the relatively sensible minority among Christians, who accept evolution.

Get the bishops and theologians on the side of science – so the argument runs – and they'll be valuable allies against the naive creationists (who probably include the majority of Christians and certainly almost all Muslims, by the way).

No politician could deny at least the superficial plausibility of this expedient, although it is disappointing how ineffective as allies the 'sensible' minority of Christians turn out to be.

The official line of the US National Academy, the American equivalent of the Royal Society, is shamelessly accommodationist. They repeatedly plug the mantra that there is 'no conflict' between evolution and religion. Michael Reiss could argue that he is simply following the standard accommodationist line, and therefore doesn't deserve the censure now being heaped upon him.

Unfortunately for him as a would-be spokesman for the Royal Society, Michael Reiss is also an ordained minister. To call for his resignation on those grounds, as several Nobel-prize-winning Fellows are now doing, comes a little too close to a witch-hunt for my squeamish taste.

Nevertheless – it's regrettable but true – the fact that he is a priest undermines him as an effective spokesman for accommodationism: "Well, he would say that, wouldn't he!"

If the Royal Society wanted to attack creationism with all fists flying, as I would hope, an ordained priest might make a politically effective spokesman, however much we might deplore his inconsistency.

This is the role that Kenneth Miller, not a priest but a devout Christian, plays in America, where he is arguably creationism's most formidable critic. But if the Society really wants to promote the accommodationist line, a clergyman is the very last advocate they should choose.

Perhaps I was a little uncharitable to liken the appointment of a vicar as the Royal Society's Education Director to a Monty Python sketch. Nevertheless, thoughts of Trojan Horses are now disturbing many Fellows, already concerned as they are by the signals the Society recently sent out through its flirtation with the infamous Templeton Foundation.

Accommodationism is playing politics, while teetering on the brink of scientific dishonesty. I'd rather not play that kind of politics at all but, if the Royal Society is going to go down that devious road, they should at least be shrewd about it. Perhaps, rather than resign his job with the Royal Society, Professor Reiss might consider resigning his Orders?
I agree with Dawkins that the position taken by Michael Reiss was not "obviously silly." In fact I think it was a really good idea.

I disagree with Dawkins when he labels Michael Reiss as an "accommodationist."1 Yes, there's an aspect of accommodation in what Reiss said, but mostly he was saying that we should confront creationist nonsense in class and explain why creationism is not science. To me, those people who want to avoid ever addressing the controversy between science and religion are the accommodationists. They are granting to religion (creationism) a privilege that they would never grant to astrologers, holocaust deniers, and advocates of quack medicine. I hope everyone agrees that the stupidity of those positions should be made clear to our students. Creationism doesn't deserve special treatment just because the basis of the silly belief is religious.

I agree with Dawkins that scientific societies like the Royal Society, the National Academies, AAAS, and even NCSE should not be promoting the false idea that science and religion are always compatible. I find it ironic that some of the same people who were most vehemently opposed to Michael Reiss are strangely silent when American societies jump into bed with religion.

Dawkins worries that forcing Micheal Reiss to resign "comes a little too close to a witch-hunt for my squeamish taste." Perhaps that's how Dawkins feels. Maybe I'm more squeamish than Richard Dawkins because I think it was a witch-hunt and I deplore the actions of some of my fellow scientists.

It will be interesting to see what happens when the witch-hunters turn their attention to the leading religious spokespersons for the National Academies and NCSE. Kenneth Miller, and Francis Collins might find themselves getting fewer speaking engagements. God only knows how they will react when they learn about Francisco Ayala. Ayala is a biologist who Chaired the National Academies Committee on Revising Science and Creationism. That's the group that published the accommodationist book Science, Evolution, and Creationism, a book that promotes the irrational Doctrine of Joint Belief.

According to a report from the University of California, Irvine, where Francisco Ayala is a Professor of Biology, he gave a lecture last May (2008) where he was asked an important question [Biology Professor Addresses Evolution and its Opponents].
When asked if religion should be removed from science courses, Ayala gave a surprising answer.

“Religion is not science, but the fact that science is compatible with religion is an important thing to state in science classes,” Ayala said.
Franscisco Ayala is not only a good biologist, he's also a Dominican priest former Dominican priest. Oops. Can you say "hypocrisy"?

I meant to imply that those who attacked Reiss are hypocrites. Where were they when the National Academies caved in to religion?


1. John Wilkins addresses this same letter and weighs in against the "accommodationist" charge. Unfortunately, his posting [Dawkins on the nose again] isn't as good as most of what John writes. I'll give him the benefit of the doubt and assume he was under the weather when he wrote it.

Wednesday, September 17, 2008

Tangled Bank #114

 
The latest issue of Tangled Bank has been published on Sciene Made Cool [The Tangled Bank #114].
Welcome to the #114th edition of the Tangled Bank, a carnival of science bloggers where you’re guaranteed to learn something new and exciting. We’ll start in the classroom, the “traditional” place for learning, ....


Send an email message to host@tangledbank.net if you want to submit an article to Tangled Bank. Be sure to include the words "Tangled Bank" in the subject line. Remember that this carnival only accepts one submission per week from each blogger.

Nobel Laureate: Otto Warburg

 


The Nobel Prize in Physiology or Medicine 1931.
"for his discovery of the nature and mode of action of the respiratory enzyme"


Otto Heinrich Warburg (1883 - 1970 ) received the Nobel Prize in Physiology or Medicine for his contributions to understanding cellular respiration. At the time he received the Nobel Prize, he was credited with discovering the "respiratory enzyme" and demonstrating that it required iron. The idea was that oxygen binds to iron during respiration in the same way that it binds to iron in hemoglobin. Here's how the discovery was described in the presentation speech on the Nobelprize.org website.

THEME:
Nobel Laureates
Definite proof that he was on the track of this well-hidden secret of Nature was obtained by the use of exact measurements of combustion in living cells or, as Warburg calls it, cell respiration. The quantitatively measured variations in the process of combustion under different conditions threw light on the nature of the respiratory ferment. Its tendency to enter into compounds with substances which combine with iron showed that it is itself an iron compound, and that its effects are due to iron.
We now know that this is incorrect. Warburg probably worked with cytochrome c which has a iron-containing heme group [Monday's Molecule #88] but cytochrome c does not bind oxygen. It is an intermediate in the oxidation-reduction pathway, contributing electrons to cytochrome c oxidase—the real oxygen binding enzyme. Cytochrome c oxidase does have an iron heme group that contributes to oxygen binding but copper atoms are also intimately involved.

This is a case where the Nobel Prize was awarded to the right person for the wrong reasons. Warburg made lots of contributions to biochemistry. He discovered flavin proteins and did seminal work on oxidation-reduction enzymes that use NAD+ as a cofactor. He also contributed significantly to our understanding of photosynthesis.

Many people believe that Warburg received a second Nobel Prize in 1944 for these other contributions but he was unable to accept it because Hitler declared that Germans, especially Jewish Germans, could not accept a foreign prize. The Nobel Committee has repeatedly declared that Warbug was not offered the prize in 1944 although he was considered a strong candidate. This declaration has not squelched the myth of two Nobel Prizes—a myth that is largely propagated on cancer websites (e.g., stopcancer.com). Warburg claimed that cancer was caused when cells switched from aerobic glycolysis to fermentation and this has made him a hero among the pseudoscience crowd. That's a tremendous disservice to one of the greatest biochemists who ever lived.



Tuesday, September 16, 2008

How RNA Polymerase Binds to DNA

Most cells contain two forms of RNA polymerase. The "core" polymerase is the part that carries out transcription of a gene where the DNA sequence is copied to produce a single-stranded RNA molecule. The core polymerase binds DNA non-specifically as you might expect for a DNA binding protein that has to travel down a large number of different genes.

When transcription is terminated the core RNA polymerase is released. In order to start a new round of transcription, the core RNA polymerase has to be directed to bind at a promoter, defined as the specific DNA sequence where transcription is initiated. There are specific DNA binding factors that bind to promoters and to RNA polymerase. That's how they direct RNA polymerase to the place where transcription has to start. These factors bind first to core polymerase forming the second form of RNA polymerase called the holoenzyme.

The binding parameters of the E. coli core polymerase and the holoenzyme have been studied in detail. In E. coli cells there are several different versions of holoenzyme. Each one contains a different initiation factor that binds to a different series of promoters. The most common initiation factor is called σ70 (sigma-70) and it binds to most of the promoters in the cell.

The steps in transcription initiation are shown in the figure. First, holoenzyme consisting of core polymerase + σ70, binds non-specifically to any stretch of DNA. It then moves along the DNA in a one-dimensional search until it finds a promoter sequence. This is followed by a local unwinding of the DNA and synthesis of a short piece of DNA.

Subsequent steps (not shown) require the dissociation of the initiation factor (σ70) and the formation of an elongation complex. RNA polymerase is then free to leave the promoter region and move down the gene making RNA.

THEME:
Transcription

The same kinds of parameters that we discussed yesterday are used to describe RNA polymerase binding [see DNA Binding Proteins and Repression of the lac Operon]. The core RNA polymerase by itself binds DNA non-specifically with an association, or binding, constant (Ka) of 1010 M-1. This is very tight binding for a DNA binding protein. Once bound to DNA the core RNA polymerase dissociates very slowly (t1/2 = 60 minutes).

The holoenzyme can also bind non-specifically. In this case the association constant is 5 × 106 M-1 and the complex dissociates rapidly (t1/2 = 3 seconds). The holoenzyme binds specifically to promoter sequences with an association constant of 2 × 1011 M-1 and t1/2 = 2 to 3 hours. Thus, the interaction of the initiation factor with core RNA polymerase has two effects: it decreases the affinity for random stretches of DNA and increases the affinity for the promoter sequence.

A typical E. coli cell contains about 5000 molecules of RNA polymerase. When the cells are growing rapidly, 2500 molecules will be bound to genes in transcription complexes. Another 1250 will be in initiation complexes of various sorts and most of the remaining RNA polymerase molecules (1200) will be bound to DNA non-specifically. Only a small number (~50) will be free in the cytoplasm.

Since the holoenzyme molecules are capable of initiating transcription on their own, a small number of the non-specifically bound molecules will accidentally transcribe short stretches of DNA. These spurious transcripts don't usually cause a problem since they are quite rare. Nevertheless, their presence means that much of the intergenic DNA in the E. coli genome is transcribed at one time or another.

Eukaryotic cells contain three different kinds of RNA polymerases [Eukaryotic RNA Polymerases]. Each one is much more complex that the bacterial enzymes but the principles of transcription initiation are the same.

In eukaryotes there are about a dozen general initiation factors for each of the different RNA polymerases. The ones for RNA polymerase II—the enzyme that transcribes protein-encoding genes—are called transcription factor IID (TFIID) etc. All of the factors are required for specific RNA polymerase binding at a promoter site and all of them associate with the core RNA polymerase to form a large holoenzyme complex. The eukaryotic general initiation factors do the same thing for eukaryotic core polymerase as the bacterial ones do for the bacterial RNA polymerase; they convert the complex to a specific DNA binding protein and lower its affinity for binding non-specifically.

As is the case in bacteria, a substantial number of holoenzyme complexes will be bound non-specifically to DNA at any one time. The proportion is much, much higher in mammalian cells because of the presence of so much junk DNA in the genome. This has the effect of soaking up a lot of holoenzyme complexes.

Since the holenzyme complexes, like those in bacteria, are capable of initiating basal levels of transcription, we should not be surprised to find spurious transciption in all parts of the genome. These transcript will be rare but they will come from any site where RNA polymerase holoenzme can bind.


Bibliography


Bustamante,C., Guthold,M., Zhu,X., and Yang,G. (1999) Facilitated target location on DNA by individual Escherichia coli RNA polymerase molecules observed with the scanning force microscope operating in liquid. J. Biol. Chem. 274, 16665-16668.
Goodrich,J.A., Cutler,G., and Tjian,R. (1996) Contacts in context: promoter specificity and macromolecular interactions in transcription. Cell 84, 825-830.
Koleske,A.J. and Young,R.A. (1995) The RNA polymerase II holoenzyme and its implications for gene regulation. Trends Biochem. Sci. 20, 113-116.
Myer,V.E. and Young,R.A. (1998) RNA polymerase II holoenzymes and subcomplexes. J. Biol. Chem. 273, 27757-27760.
Ossipow,V., Tassan,J.P., Nigg,E.A., and Schibler,U. (1995) A mammalian RNA polymerase II holoenzyme containing all components required for promoter-specific transcription initiation. Cell 83, 137-146.
Pan,G., Aso,T., and Greenblatt,J. (1997) Interaction of elongation factors TFIIS and elongin A with a human RNA polymerase II holoenzyme capable of promoter-specific initiation and responsive to transcriptional activators. J. Biol. Chem. 272, 24563-24571.
Ricchetti,M., Metzger,W., and Heumann,H. (1988) One-Dimensional Diffusion of Escherichia-Coli Dna-Dependent Rna-Polymerase - A Mechanism to Facilitate Promoter Location. Proceedings of the National Academy of Sciences of the United States of America 85, 4610-4614.
Shimamoto,N. (1999) One-dimensional diffusion of proteins along DNA. Its biological and chemical significance revealed by single-molecule measurements. J. Biol. Chem. 274, 15293-15296.
Singer,P. and Wu,C.W. (1987) Promoter search by Escherichia coli RNA polymerase on a circular DNA template. J. Biol. Chem. 262, 14178-14189.
Singer,P.T. and Wu,C.W. (1988) Kinetics of promoter search by Escherichia coli RNA polymerase. Effects of monovalent and divalent cations and temperature. J. Biol. Chem. 263, 4208-4214.
von Hippel,P.H. (2007) From "simple" DNA-protein interactions to the macromolecular machines of gene expression. Annual Review of Biophysics and Biomolecular Structure 36, 79-105.
von Hippel,P.H. and Berg,O.G. (1989) Facilitated target location in biological systems. J. Biol. Chem. 264, 675-678.

Genetics and Race

 
John Hawks has some interesting things to say about genetics and race based on a New York Times article about David Goldstein. The article can be found at: A Dissenting Voice as the Genome Is Sifted to Fight Disease, and the Hawks' posting is at: David Goldstein profile.

Scientists are discovering more and more genetic differences between human races and this is starting to cause some problems as described in the New York Times article ...
Another pursuit that interests him, one of high promise for reconstructing human evolutionary history, is that of discovering which genes bear the mark of recent natural selection. When a new version of a gene becomes more common, it leaves a pattern of changes that geneticists can detect with various statistical tests. Many of these selected genes reflect new diets or defenses against disease or adaptations to new climates. But they tend to differ from one race to another because each human population, after the dispersal from Africa some 50,000 years ago, has had to adapt to different circumstances.

This newish finding has raised fears that other, more significant differences might emerge among races, spurring a resurrection of racist doctrines. “There is a part of the scientific community which is trying to make this work off limits, and that I think is hugely counterproductive,” Dr. Goldstein said.
John Hawks is an expert in these kinds of studies so it's interesting to read his comments. Note that there's no disagreement over the facts; races are genetically different. I disagree with Hawks and Goldstein on the cause of some of this variation. In my opinion they are placing too much emphasis on selection as the cause of variation between species and not enough emphasis on chance. Differences in ABO blood type frequencies, for example, are probably not due to selection.

At the end of his posting Hawks mentions a quotation from Theodosius Dobzhansky. This is a quotation that everyone should keep in mind as they enter the debate. You can find out more by reading a 2006 posting about Dobzhansky on continuing human evolution. Here's the actual Dobzhansky quotation from that posting ...
The chief reasons why so many people are loath to admit the genetic variability of socially and culturally significant traits are two. First, human equality is stubbornly confused with identity, and diversity with inequality, as though to be entitled to an equality of opportunity, people would have to be identical twins. Human diversity is not incompatible with equality. Secondly, it is futile to look for one-to-one correspondence between cultural forms and genetic traits. Cultural forms are not determined by genes, but their emergence and maintenance are made possible by the genetically conditioned human diversity
Let me sound a note of caution to those who wish to comment. The fact that humans races might be genetically different says absolutely nothing at all about equality and racism. For this thread only, I will delete any comments where the author is confused about this distinction. This is a discussion about science and whether some scientific investigations should be censored because they might be misinterpreted.

Hawks doesn't allow comments on his blog. This is such an interesting topic that I thought I'd mention it here to get some feedback.


[Image Credit: The image is obviously the cover of Scientific American from December 2003. This is one of the most blatant examples of political correctness ever published in a prestigious journal and it's one more example of the decline of Scientific American. It doesn't take much to recognize that the faces on the cover are identical except for skin color. As if that's all there is to human populations.]

Monday, September 15, 2008

DNA Binding Proteins

Proteins that bind to DNA can be divided into two groups: those that bind to a specific DNA sequence and those that bind non-specifically. Proteins in the latter category include those required for DNA replication, repair, and recombination, as well as packaging proteins like the histones.

Proteins that bind to specific DNA sequences are often activators or repressors involved in regulating gene expression. These are proteins that interact with a short, well-defined, nucleotide sequence found near the start site for transcription. The purpose of this posting is to review some of the basic characteristics of such proteins using lac repressor as a well studied example.

The figure below shows the structure of a lac repressor dimer bound to DNA.


The rate and strength of binding of lac repressor to DNA has been the subject of many papers over the course of several decades. Lac repressor binds tightly to a specific DNA sequence at the beginning of the lac operon. When it is bound to DNA it prevents, or represses, transcription of the operon.

Now, here's the important point: all specific DNA binding proteins also bind DNA non-specifically. In many cases it's part of the search mechanism for the specific binding site. In the case of lac repressor, for example, the protein binds to any old place on the DNA molecule and slides along the DNA searching for a specific binding sequence. After sliding for a second or so it falls off and re-binds to another part of the DNA molecule.

Once the repressor finds its specific binding site it remains bound for about twenty minutes. In biochemical terms we say that it's bound half-life is 20 minutes. The strength of binding is described by an equilibrium binding constant (KB) that reflects the ratio of free repressor to bound repressor. For lac repressor the binding constant is one of the highest measured for any DNA binding protein (= 1013 M-1). What this means is that lac repressor binds very tightly to its specific binding site.

The equilibrium binding constant for non-specific binding is only 4 × 104 M-1. Thus, repressor binds nearly one billion (109) times more strongly to its specific binding site than to any old stretch of DNA. That's very impressive. In fact, it's one of the largest differences known for any DNA binding protein. When bound non-specifically the half-life is measured in seconds. It falls off (dissociates) rapidly.

These measurements have interesting consequences. There are about ten repressor molecules in each cell (E. coli). At any given time one of them will almost certainly be at its binding site near the lac operon but the other nine will be bound to DNA somewhere else. There are millions of places where the repressor can bind non-specifically but only one where it can bind specifically.1

Some of these non-specific binding sites will, by chance, resemble the sequence of the specific binding site so lac repressor will linger longer at those sites than at sites that are completely unrelated to the specific binding sites. The point is that even for a highly specific DNA binding protein like lac repressor, most of the protein is bound to other sites most of the time.

For lac repressor, this fundamental property doesn't have serious consequences but for activators it's a different story. An activator is a protein that binds near a gene and recruits RNA polymerase to the site where it can begin transcription. Since most activators will be bound to random DNA sequences most of the time, the chances of accidentally recruiting RNA polymerase to begin a spurious transcript are quite high. From what we know about basic biochemistry, we expect that random spurious transcription should be quite common.

Tomorrow we'll look at RNA polymerase binding in the presence and absence of a specific DNA binding activator.


1. The specific binding sites are called operators. There are actually three different operator sequences to which lac repressor can bind but that doesn't make much different for the point I trying to make.

Random Genetic Drift Simulator

 
Here's a nice Java applet from Kent Holsinger at the University of Connecticut [Genetic Drift]. Thanks to Pascal for the link.




It's the Leader, Stupid

 
Canada is in the middle of a federal election and the Liberal Party under Stéphane Dion is going to lose a lot of seats. The losses may even be enough to give our current Prime Minister, Stephen Harper of the Conservative Party, a majority.

This is not an election about the economy. It's not about Canada's foreign policy. It's not about the environment and the carbon tax of the Liberal party. It's not about health care and it's not about education.

It's about leadership. Stéphane Dion does not inspire confidence and a lot of Liberal supporters, including me, can't bring themselves to vote for him. We want him to resign as soon as possible and we're willing to vote for someone else in order to make sure that Dion gets the message.


Monday's Molecule #88

 
For this week's quiz you need to identify the top molecule. The bottom one is a hint so you can get the correct molecule.

There's a connection between today's molecule and a Nobel Prize but the connection is indirect. I'm looking for the person who discovered the molecule. This person won the Nobel Prize for the discovery and for identifying the function but, as it turns out, the function was incorrect.

The first one to correctly identify the molecule and name the Nobel Laureate, wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first collected the prize. There are three ineligible candidates for this week's reward. You know who you are.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.

Comments will be blocked for 24 hours. Comments are now open.

UPDATE: We have a winner! Dima Klenchin from the University of Wisconsin figured out that the molecule was cytochrome c from some organism. (It was tuna, Thunnus alalungo, PDB 5CYT.) The Nobel Laureate was difficult but Dima uses scientific reasoning to get the correct answer: Otto Warburg (1931). Congratulations Dima!


The Michael Reiss Issue

 
I agree with Michael Reiss that we should challenge creationists head-on by debunking their claims in science class. When students bring up bogus objections to evolution we should make sure they understand why they are wrong. It's all part and parcel of teaching critical thinking—the main objective in education [see The Royal Society and Teaching Creationism].

Some people disagree. They think that even mentioning these bogus objections in class lends credence to creationism. This is what I call the Ostrich Approach to teaching.

The New Humanist has an article on the controversy [Creationism in schools row rumbles on]. Here's the issue as they see it.
The issue of creationism in class is a difficult one. Critics such as Kroto, Roberts and Dawkins are understandably wary of religious ideas being allowed anywhere near school science labs, especially at a time when creationist organisations and proponents of Intelligent Design are stepping up efforts to shoehorn their ideas into science curricula. But if we take Reiss at his word (and if you read the blog posted on the Guardian last week, it's clear he wasn't suggesting creationism should be taught), then wasn't he just pointing out that the classroom should be a forum for free and open debate, and teachers must be ready to enter discussion with their pupils, and put them right when the views they bring from home clearly contradict the overwhelming evidence for evolution? Isn't this part of the aim of education?
PZ Myers has weighed in against Reiss [Michael Reiss's big mistake]. According to PZ ...
Michael Reiss, the director of education, is pushing this idea with a noble and reasonable intent: he thinks it is the only way to reach some students who will shut off learning if their religious biases are challenged. Unfortunately, he's also suggesting that non-science/anti-science concepts should be specified as a course objective in science classes, he's buying into common creationist propaganda ploy, and he's asking for unwarranted deference for wrong ideas held for unscientific reasons by students. He argues for respecting misplaced concerns.
I don't agree with PZ. I think he misunderstands what Michael Reiss is advocating and, furthermore, I think he's projecting an American perspective on to teaching in the UK.

The New Humanist website is running a poll on the question. The poll asks for your views on Michael Reiss' opinion. The choices are:
  • Outrageous – creationism has no place in schools and he should be removed from his post

  • Irresponsible – no one wants to stifle debate, but his comments risk encouraging the encroachment of creationism into schools

  • Misunderstood – his sensible comments on free debate were misrepresented by hysterical media

  • Brave – In a scientific community hostile to religion, he has made a stand for open debate
So far 54% are calling for Reiss' dismissal and 41% say he is irresponsible. I voted for the third option on the assumption that "hysterical media" includes "hysterical bloggers."


GrrlScientist on the Sandwalk

 
If you send me a picture of you on the Sandwalk I'll post it here. GrrlScientist recently visited Down House and took some pictures of the Sandwalk [Visiting Darwin's Home, Part 4: The Sandwalk].

She is very shy so there are no pictures of her, or Prof. Steve Steve, on the Sandwalk. In spite of that oversight, I'm stealing her pictures so I can share them with Sandwalk readers.

PZ and I visited Down House two years ago on a trip to London. We were away for about eight days and we also visited the Natural History Museum, Wesminster Abby (Darwin's tomb), Oxford, and a few historic pubs. I think the total cost was about $1500 each. I wonder how many people would be interested in such a trip if I (we?) were to organize another?










The God Gene and Evolutionary Psychology

 
Most of you have heard about the God gene by now. Strictly speaking, it isn't a God "gene" but a God allele. It's the variant that makes you believe in God. According to its proponents, most people are homozygous for this allele. That's why it's not their fault.

Evolutionary psychology has lots of similar examples of behavioral genes that put the blame on genetics. Here's a short video that explains the idea of genes controlling behavior.




[Hat Tip: John Wilkins, who doesn't find it funny because he's a reductionist mechanist and an adaptationist. ]

Illustrating Random Genetic Drift

 
John Hawks has been generating some graphs for his class in order to illustrate random genetic drift. See how he does it at Some genetic drift graphs with Mathematica.


The important point, which most students don't get, is that eventually one allele will become fixed in the population and the other will be eliminated for ever.1


1. In a simple two allele situation in a sexual population.

Sunday, September 14, 2008

Gene Genie #37

 
The 37th edition of Gene Genie has been posted at The Genetic Genealogist [Gene Genie 37: Human Genomes Are a Dime a Dozen].
Welcome to the September 14, 2008 edition of Gene Genie! Bloggers have begun to pick up posting with the end of summer, and it seems like everyday there’s a bunch of new interesting posts about the human genome.
The beautiful logo was created by Ricardo at My Biotech Life.

The purpose of this carnival is to highlight the genetics of one particular species, Homo sapiens.

Here are all the previous editions .....
  1. Scienceroll
  2. Sciencesque
  3. Genetics and Health
  4. Sandwalk
  5. Neurophilosophy
  6. Scienceroll
  7. Gene Sherpa
  8. Eye on DNA
  9. DNA Direct Talk
  10. Genomicron
  11. Med Journal Watch
  12. My Biotech Life
  13. The Genetic Genealogist
  14. MicrobiologyBytes
  15. Cancer Genetics
  16. Neurophilosophy
  17. The Gene Sherpa
  18. Eye on DNA
  19. Scienceroll
  20. Bitesize Bio
  21. BabyLab
  22. Sandwalk
  23. Scienceroll
  24. biomarker-driven mental health 2.0
  25. The Gene Sherpa
  26. Sciencebase
  27. DNA Direct Talk
  28. Greg Laden’s Blog
  29. My Biotech Life
  30. Gene Expression
  31. Adaptive Complexity
  32. Highlight Health
  33. Neurophilosophy
  34. ScienceRoll
  35. Microbiology Bytes
  36. Human Genetic Disordrs
  37. The Genetic Genealogist






The Royal Society and Teaching Creationism

 
Michael Reiss is a practicing priest in the Church of England. He is also director of education in The Royal Society. Reiss wrote an article about teaching creationism in schools. The complete article was posted on guardian.co.uk [Science lessons should tackle creationism and intelligent design].

This article is stirring up a lot of controversy because many people are interpreting it to be support for teaching creationism as a scientific viewpoint. That's not how I interpreted it. I thought Michael Reiss was saying the same thing I advocate. Here is the relevant part of the article so you can judge for yourself.
I feel that creationism is best seen by science teachers not as a misconception but as a world view. The implication of this is that the most a science teacher can normally hope to achieve is to ensure that students with creationist beliefs understand the scientific position. In the short term, this scientific world view is unlikely to supplant a creationist one.

So how might one teach evolution in science lessons, say to 14 to 16-year-olds? Many scientists, and some science educators, fear that consideration of creationism or intelligent design in a science classroom legitimises them.

For example, the excellent book Science, Evolution, and Creationism published by the US National Academy of Sciences and Institute of Medicine, asserts: "The ideas offered by intelligent design creationists are not the products of scientific reasoning. Discussing these ideas in science classes would not be appropriate given their lack of scientific support."

I agree with the first sentence but disagree with the second. Just because something lacks scientific support doesn't seem to me a sufficient reason to omit it from a science lesson. When I was taught physics at school, and taught it extremely well in my view, what I remember finding so exciting was that we could discuss almost anything providing we were prepared to defend our thinking in a way that admitted objective evidence and logical argument.

So when teaching evolution, there is much to be said for allowing students to raise any doubts they have (hardly a revolutionary idea in science teaching) and doing one's best to have a genuine discussion. The word 'genuine' doesn't mean that creationism or intelligent design deserve equal time.

However, in certain classes, depending on the comfort of the teacher in dealing with such issues and the make-up of the student body, it can be appropriate to deal with the issue. If questions or issues about creationism and intelligent design arise during science lessons they can be used to illustrate a number of aspects of how science works.
The other approach is the one I call the "Ostrich" approach. It would ban all mention of creationism and refuse to even discuss any objections to evolution that students might have. This approach avoids the controversy altogether by claiming that creationism isn't science and therefore shouldn't be taught in science class.

That's just plain silly, in my opinion. We all know that creationist students have a lot of so-called "objections" to evolution and by ignoring them in evolution classes we are not doing our job. We need to face those "objections" and deal with them by explaining why they aren't scientific. If we don't do that, then we shouldn't be surprised when students accept the word of their pastor over that of their science teacher. You can be certain that their pastor doesn't limit his/her teaching to religion.

We agree that creationism isn't science. It's an attack on science and the best place to defend against such attacks is in a science class.


[Hat Tip: RichardDawkins.net where you'll find plenty of discussion in the comments.]