Friday, November 24, 2006

Island Mice May Evolve Faster: From One Species To Six In 500 Years

SOURCE: Genome News Network

AUTHOR: Bijal P. Trivedi

COMMENTARY: Allen MacNeill

An alert Evolution List reader has already pointed me to an article that first appeared on April 28, 2000, concerning the unusually rapid speciation of common European mice on the island of Madeira. Apparently, these mice were brought to the island on sailing ships, most likely from Portugal. Since such ships were very small, the total size of the founding populations would have been extremely small; probably less than a dozen individuals (and certainly less than a hundred).

This would certainly qualify as precisely the kind of founder population that I described in the previous post concerning a possible mechanism for chromosomal speciation. In particular, it is extremely interesting that the mice in question have apparently speciated in less than 500 years, and that the mechanism underlying this speciation has involved multiple chromosomal fusions.

Here’s the full article describing the research (commentary follows):

Janice Britton-Davidian spent several weeks in 1999 placing hundreds of mousetraps all over the semi-tropical island of Madeira and discovered what may be an example of "rapid evolution." She caught hundreds of small brown mice that look pretty much alike but that are genetically distinct—a very unusual thing for such a small, geographically contained place. It normally takes thousands to millions of years for one species of animal to diverge to become two. On Madeira, one species may have evolved into six in the space of just 500 years.

Britton-Davidian, an evolutionary biologist at Université Montpellier II in Montpellier, France, showed that populations of Maderian mice have between 22 and 30 chromosomes, even though their ancestors, who first arrived with the Portuguese in the 15th century, had 40.

Madeira is a rugged volcanic island with sharp black cliffs that block all but a few isolated rocky shores. Only a few small villages decorate the strip of coast. The Portuguese were first to inhabit the island, bringing with them the mice that Britton-Davidian so avidly seeks. As the Portuguese founded small settlements around the island, they inadvertently deposited small groups of mice at each stop. And, for the last five centuries, mountainous barriers have prevented these coastal colonies of rodents from commingling.

Britton-Davidian collected hundreds of mice from about 40 locations around the island and found six distinct populations. The common brown house mouse of Europe, presumably the ancestor of the Madeira mice, has 40 chromosomes, but the six families of Madeiran mice have between 22 and 30.

The current families of Madeiran mice are not short of genetic material. They have not lost any DNA. What happened is this: over time, some of the chromosomes fused together, packing more DNA into some chromosomes. Each of the six unique populations of mice on Madeira has its own special assembly of fused chromosomes. Each group of mice may now be its own species.

The diversity of fused chromosomes seems to have occurred in just 500 years, or between 1,500-2,000 generations of mice, says Britton-Davidian. Furthermore, the huge diversity in chromosomes has evolved solely from geographic isolation rather than adaptations to different environments.

"What is surprising is how fast this has taken place," says Scott Edwards, an evolutionary biologist from the University of Washington, in Seattle. Based on fossil records of sea urchins and invertebrates, evolution of different species is thought to take thousands to millions of years. "But this is an interesting case because it may prove to be an extreme case of rapid speciation," says Edwards.

Britton-Davidian wants to know whether these populations of mice have evolved into different species or whether they are on the cusp of speciation. A species is defined as a group of organisms that can mate and produce fertile offspring.

One of Britton-Davidian's most surprising findings is that she and her colleagues found no mice that are hybrids among any of the six groups. "This might be because the hybrids are infertile or they may be less fit than the parents and unable to survive," says Britton-Davidian. Other explanations could be that the groups have been geographically isolated and have not had the chance to mate, or that the mice "recognize each other as different and choose not to mate."

Britton-Davidian has taken some mice from Madeira back to her lab in France and will try interbreeding the six populations to confirm whether the hybrid mice are infertile, which, if they are, would imply that the different groups were in the process of speciation. Her team will also observe the mice to see whether they show behavioral or physical differences.


Britton-Davidian, J. et al. Rapid chromosomal evolution in island mice. Nature 403, 158 (January 13, 2000).


I must admit that I did not expect to find evidence supporting my hypothesis so quickly; thanks to list reader Zachriel for finding the article posted above. Several items in the article immediately struck me:

• The mice in question were “seeded” in six isolated communities, presumably unintentionally (i.e. in boxes, foodstuffs, or by climbing down mooring lines). These would qualify as six separate, very small founder populations.

• The mountains separating the six populations would effectively isolate the populations, preventing gene flow and maintaining the populations at very low sizes (i.e. the surrounding environments would not be conducive to allowing the mice populations to expand, as they are adapted to living in human habitations).

• The six populations differ almost entirely in chromosome number, but not in apparent phenotype, as predicted by my hypothesis.

I haven’t had time to follow up and check to see if Britton-Davidian has been able to correlate the chromosomal differences between the six different mice populations and their behavior, etc. As readers of the previous post might suspect, my hypothesis does not necessarily predict that there will be any such differences at all. On the contrary, chromolocal mutations (such as the multiple fusions found in the Madeiran mice) don’t change the genetic information, they simply rearrange where it is located in the genome.

If the foregoing does indeed support my hypothesis (and if the hypothesis eventually is shown to be valid) it says something very interesting about speciation and its relationship to natural selection (and, by extension, the “modern evolutionary synthesis”). According to the “modern synthesis,” speciation is the result of geographic isolation and diversifying selection (as originally proposed by Mayr and Dobzhansky), with selection playing an important role in reinforcing species differences via the intensification of “isolating mechanisms.”

However, my “first-degree inbreeding” hypothesis implies just the opposite: that the genetic processes that isolate populations (which subsequently become species) happen first (i.e. chromolocal mutations, etc.), thereby effectively isolating the populations entirely by accident, and that later the already isolated populations begin to diverge in character as the result of selection, drift, etc.

It also implies very strongly that macroevolution (defined as evolution at the species level and above) actually happens virtually instantaneously, as the result of genomic rearrangements such as chromolocal mutations, with phenotypic diversification taking much longer. This squares with the fundamental difference between cladogenesis (i.e. macroevolution) and anagenesis (i.e. microevolution), as the former is essentially instantaneous at the moment of divergence of a new clade, whereas the latter takes time...lots of time, as Darwin first pointed out.

In closing, it is interesting to contemplate the mounting evidence for surprisingly rapid cladogenesis in nature, as shown by the cichlids of Lake Victoria and the mice of Madeira. As I have said before, these newly emerging ideas are diffficult to reconcile with some of the main tenets of the "modern evolutionary synthesis" (although they fit well with Darwinian theory overall). Once again, "The modern synthesis is dead; long live the evolving synthesis!"

I would really appreciate comments, suggestions, and especially criticisms of the foregoing and of my proposed hypothesis. Just click on my name, below, and send me an email, or just click on the “Comments” link. I’ll get your message either way, and will respond as quickly as ever I am able.


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Thursday, November 23, 2006

Hypothesis: First-Degree Inbreeding Facilitates Chromosomal Speciation

AUTHOR: Allen MacNeill

SOURCE: Original essay

COMMENTARY: That's up to you...

Happy Thanksgiving!

To help you enjoy the holiday, let me offer you a hypothesis that I have been working on to explain the origin of species in animals. The inspiration for this hypothesis was a debate at Uncommon Descent in which I have been embroiled for the past few days. The debate began with a discussion of the possibility of "virgin birth" in humans. The poster, DaveScot (not his real name) started out with a description of meiosis that contained an egregious error: that the first division of meiosis results in two diploid daughter cells. As every introductory biology student knows, this is incorrect: the first division of meiosis produces two haploid daughter cells in which the chromosomes are still double-stranded. The second division of meiosis is essentially a mitotic division, separating the sister chromatids in the double-stranded chromosomes of the first-division daughter cells.

The debate moved on, eventually centering on the subject of the chromosomal basis for speciation. I mentioned that speciation is the result of genetic isolation, and that in many cases (but not all) it is associated with chromosomal fission, fusion, inversion, and translocation events. For example, one of the main differences between humans and other great apes is that humans have one less pair of chromosomes; 46 instead of 48. Recent genomic research has shown that this difference is the result of the fusion of two of the chromosomes of great apes to form the human chromosome #2. This led to the following question from one of the participants in the debate:

"Wouldn't this fusion event have to occur within at least two members- one male, one female- of the same population in order for it to have any chance of getting passed on?"

To which I answered:

No. All that would need to happen to make this possible would be for two first-degree relatives carrying the translocation to mate and have offspring. First degree relatives (i.e. parents and offspring or full siblings) can easily have the same chromosomal mutation (i.e. a fusion/fission/translocation/inversion), as they would inherit it from a single parent. If they were to mate with each other (a not uncommon event among non-humans...and even among some humans), they would be able to produce fertile offspring carrying the same chromosomal mutation.

Yes, it is true that first degree mating carries with it the possibility of reinforcement of recessive lethal alleles. However, as many geneticists and evolutionary biologists have repeatedly pointed out, this is actually beneficial to the population within which such reinforcement happens, as the alleles are removed from the population as a result.

In other words, mating between first degree genetic relatives within a small, isolated population would have the effect of both removing deleterious alleles from the population and allowing chromosomal mutations to spread throughout the population, especially if such mutations were at all beneficial (although they would diffuse almost as well if they were selectively neutral, as would probably be the case given that no change in overall genetic information would have occurred).

Furthermore, the hypothesis that I have presented above squares very well with the currently prevailing theory of speciation: that of peripatric speciation, as first proposed by Ernst Mayr. According to Mayr's theory, speciation occurs most often in small, isolated populations on the periphery of large, panmictic populations. There is abundant natual history evidence that this is the case, especially in animals.

However, no one has yet explained how peripatric speciation would come to be associated with the kinds of chromosomal changes that we have been discussing. My hypothesis – that first-degree inbreeding facilitates chromosomal speciation – is an attempt to reconcile those two observations.

In a large, panmictic population, selection would tend to eliminate individuals who mate with first-degree relatives as a result of decreased viability due to inbreeding depression and the increased frequency of expression of homozygous lethal alleles.

However, in very small, isolated populations individuals who occasionally mate with first degree relatives (i.e. "facultative first degree inbreeders") could easily have a selective advantage of individuals who avoid mating with first degree relatives (i.e. "obligate outbreeders").

Males in particular would tend to loose less as the result of mating with first degree relatives, as their parental investment in offspring is lower (i.e. they can waste gametes and even zygotes by mating with their first degree relatives, without significantly decreasing their reproductive success).

However, even females can cut their losses by mating with first degree relatives if the likely alternative is failure to mate at all due to unavailability of non-relatives. This would especially be the case in small, isolated populations, which are exactly the kind of populations in which speciation is most likely to occur.

The effects described above would be facilitated by increased genomic homogeneity, such as would result from genetic bottlenecks and founder effects. This is because close inbreeding intensifies genomic homogeneity and decreases genetic variation, especially in isolated populations with decreased gene flow from other populations.

This hypothesis – that first degree inbreeding facilitates chromosomal speciation – immediately suggests a series of predictions, all of which are empirically testable:

• The frequency of mating between first degree relatives should be inversely correlated with effective breeding population size. That is, the smaller the effective breeding population, the greater the frequency of mating between first degree relatives (i.e. “first degree inbreeding”).

• The increased frequency of “first degree inbreeding” in such populations should be more pronounced in males. That is, males should be more likely to attempt mating with first degree relatives, especially in small, isolated populations.

• The frequency of “chromolocal mutations” (that is, chromosomal fission/fusion/inversion/translocation mutations) should also be inversely correlated with effective breeding population size. That is, the smaller the effective breeding population, the greater the frequency of viable “chromolocal mutations.”

• Peripatric speciation events should be correlated with small population size, chromolocal mutations, and first degree inbreeding.

• Speciation resulting from chromolocal mutations should be much less common in large, panmictic populations.

• First degree inbreeding should also be much less common in large, panmictic populations.

• The success rate of artificial (i.e. facilitated/forced) first degree mating should be directly correlated with the degree of inbreeding. That is, the more inbred a population, the more successful artificial first degree inbreeding should be.

• Paleogenomic analysis should find close correlations between genetic bottlenecks, founder events, and peripatric speciation events and the frequency of chromolocal mutations and genetic homogeneity (resulting from first degree inbreeding).

• Relatively large changes in phenotype resulting from chromolocal effects should be more common in small, isolated populations.

• Speciation should be easier (and therefore more frequent) among asexually reproducing eukaryotes, such as plants and parthenogenic animals (among whom aneuploidy is largely irrelevant).

Let me stress two things about the foregoing:

• What I am suggesting is, at this stage, merely a hypothesis, but one that generates a series of immediately testable predictions.

• The hypothesis is, of course, based on the idea that incest (i.e. first degree inbreeding) is the most likely explanation for the diffusion of chromolocal mutations throughout small, isolated populations of animals. Let me stress as strongly as possible that I am NOT advocating incest, I am simply pointing out that first degree inbreeding would facilitate the kind of chromolocal mutations that are often correlated with species differences in animals. The same is also true for plants, of course, but in plants we don't call it "incest," we call it "self-pollination."

I would like to also add at the end of this presentation that my reading of John Davison's papers in which he details his "semi-meiotic hypothesis" for the origin of species were an indirect inspiration for my own efforts. While his hypothesis would work, its most significant drawback is that it requires an almost unlimited number of independent "reinventions" of the same mechanism (i.e. semi-meiosis) for speciation that results from chromolocal effects to be the basis for speciation throughout the animal kingdom. Not impossible, but extremely unlikely.

By contrast, my "first degree inbreeding hypothesis" does not require independent "reinventions" of semi-meiosis at all. The only thing it requires is that first-degree inbreeding occur in small, isolated populations of animals, an easily testable prediction that does not require elaborate genetic mechanisms to produce the predicted outcome: that is, genetic isolation and subsequent speciation.

I am a little perplexed at why no one has yet proposed this mechanism, given the fact that it is already used as the explanation for speciation in plants via polyploidy. The only explanation that seems reasonable to me is that most evolutionary biologists assume that animals will always avoid mating with first-degree relatives as a result of the increased frequency of inbreeding depression and expression of homozygous lethal alleles that result from it.

Anyway, that's my hypothesis in brief. Oh, and one more thing: why the turkey at the head of this post? To commemorate Thanksgiving, of course, but also because turkeys are known to exhibit significant numbers of parthenogenesis. That is, a significant proportion of male turkeys are the result of the development of an unfertilized egg. They are male, not female (as would be the case in parthenogenetic mammals) because males are the homogametic sex in birds; they are ZZ, whereas females are ZW (the Z and W chromosomes corresponding in function to the X and Y chromosomes in mammals). It has not escaped my notice that parthenogenesis would greatly facilitate the kind of chromosomal speciation I have outlined above. Hence, the turkey can stand as an emblem of the First-Degree Inbreeding Hypothesis for Chromosomal Speciation in Animals.

Have a great turkey day, folks!

Comments, criticisms, and suggestions are warmly welcomed!


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Tuesday, November 14, 2006

Unraveling Where Chimp And Human Brains Diverge

SOURCE: Terra Daily News

COMMENTARY: Allen MacNeill

Just in time for our discussion of human-chimpanzee differences in our evolution course at Cornell, here is an article describing recent research into how human an chimpanzee brains differ. Commentary follows:

Los Angeles CA (SPX) Nov 14, 2006: Many of the human-specific gene networks identified by the scientists related to learning, brain cell activity and energy metabolism.

Six million years ago, chimpanzees and humans diverged from a common ancestor and evolved into unique species. Now UCLA scientists have identified a new way to pinpoint the genes that separate us from our closest living relative - and make us uniquely human. The Proceedings of the National Academy of Sciences reports the study in its Nov. 13 online edition.
"We share more than 95 percent of our genetic blueprint with chimps," explained Dr. Daniel Geschwind, principal investigator and Gordon and Virginia MacDonald Distinguished Professor of Human Genetics at the David Geffen School of Medicine. "What sets us apart from chimps are our brains: homo sapiens means 'the knowing man.'

"During evolution, changes in some genes altered how the human brain functions," he added. "Our research has identified an entirely new way to identify those genes in the small portion of our DNA that differs from the chimpanzee's."

By evaluating the correlated activity of thousands of genes, the UCLA team identified not just individual genes, but entire networks of interconnected genes whose expression patterns within the brains of humans varied from those in the chimpanzee.

"Genes don't operate in isolation - each functions within a system of related genes," said first author Michael Oldham, UCLA genetics researcher. "If we examined each gene individually, it would be similar to reading every fifth word in a paragraph - you don't get to see how each word relates to the other. So instead we used a systems biology approach to study each gene within its context."

The scientists identified networks of genes that correspond to specific brain regions. When they compared these networks between humans and chimps, they found that the gene networks differed the most widely in the cerebral cortex -- the brain's most highly evolved region, which is three times larger in humans than chimps.

Secondly, the researchers discovered that many of the genes that play a central role in cerebral cortex networks in humans, but not in the chimpanzee, also show significant changes at the DNA level.

"When we see alterations in a gene network that correspond to functional changes in the genome, it implies that these differences are very meaningful," said Oldham. "This finding supports the theory that variations in the DNA sequence contributed to human evolution."

Relying on a new analytical approach developed by corresponding author Steve Horvath, UCLA associate professor of human genetics and biostatistics, the UCLA team used data from DNA microarrays - vast collections of tiny DNA spots -- to map the activity of virtually every gene in the genome simultaneously. By comparing gene activity in different areas of the brain, the team identified gene networks that correlated to specific brain regions. Then they compared the strength of these correlations between humans and chimps.

Many of the human-specific gene networks identified by the scientists related to learning, brain cell activity and energy metabolism.

"If you view the brain as the body's engine, our findings suggest that the human brain fires like a 12-cylinder engine, while the chimp brain works more like a 6-cylinder engine," explained Geschwind. "It's possible that our genes adapted to allow our brains to increase in size, operate at different speeds, metabolize energy faster and enhance connections between brain cells across different brain regions."

Future UCLA studies will focus on linking the expression of evolutionary genes to specific regions of the brain, such as those that regulate language, speech and other uniquely human abilities.


Sounds to me like the differences are probably the result of different patterns of gene regulation in humans and chimps, rather than entirely different coding regions in the DNA of the two species. In other words, we share a common set of genes for making our brains, but those genes are regulated differently in the two species. This would explain a lot: why, for example, there is so little difference between human and chimp DNA, and how the two species could have diverged so quickly from a common ancestor six million years ago (or less, as some of the archaeological data seem to indicate).

It will be very interesting to see how this story develops, as we get higher and higher resolution "maps" of human and chimp brains and the genetic mechanisms that produce them.


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Friday, November 10, 2006

Thank Goodness! for Daniel Dennett


AUTHOR: Daniel Dennett

COMMENTARY: Allen MacNeill

I thought readers of this blog might be interested in the fact that notorious atheist (and "Darwinist") Daniel Dennett very nearly died of a dissecting aortic aneurism last week. Did he "find God" like Anthony Flew and A. J. Ayer? Not quite…

by Daniel C. Dennett

There are no atheists in foxholes, according to an old but dubious saying, and there is at least a little anecdotal evidence in favor of it in the notorious cases of famous atheists who have emerged from near-death experiences to announce to the world that they have changed their minds. The British philosopher Sir A. J. Ayer, who died in 1989, is a fairly recent example. Here is another anecdote to ponder.

Two weeks ago, I was rushed by ambulance to a hospital where it was determined by c-t scan that I had a "dissection of the aorta"—the lining of the main output vessel carrying blood from my heart had been torn up, creating a two—channel pipe where there should only be one. Fortunately for me, the fact that I'd had a coronary artery bypass graft seven years ago probably saved my life, since the tangle of scar tissue that had grown like ivy around my heart in the intervening years reinforced the aorta, preventing catastrophic leakage from the tear in the aorta itself. After a nine-hour surgery, in which my heart was stopped entirely and my body and brain were chilled down to about 45 degrees to prevent brain damage from lack of oxygen until they could get the heart-lung machine pumping, I am now the proud possessor of a new aorta and aortic arch, made of strong Dacron fabric tubing sewn into shape on the spot by the surgeon, attached to my heart by a carbon-fiber valve that makes a reassuring little click every time my heart beats.

As I now enter a gentle period of recuperation, I have much to reflect on, about the harrowing experience itself and even more about the flood of supporting messages I've received since word got out about my latest adventure. Friends were anxious to learn if I had had a near-death experience, and if so, what effect it had had on my longstanding public atheism. Had I had an epiphany? Was I going to follow in the footsteps of Ayer (who recovered his aplomb and insisted a few days later "what I should have said is that my experiences have weakened, not my belief that there is no life after death, but my inflexible attitude towards that belief"), or was my atheism still intact and unchanged?

Yes, I did have an epiphany. I saw with greater clarity than ever before in my life that when I say "Thank goodness!" this is not merely a euphemism for "Thank God!" (We atheists don't believe that there is any God to thank.) I really do mean thank goodness! There is a lot of goodness in this world, and more goodness every day, and this fantastic human-made fabric of excellence is genuinely responsible for the fact that I am alive today. It is a worthy recipient of the gratitude I feel today, and I want to celebrate that fact here and now.

To whom, then, do I owe a debt of gratitude? To the cardiologist who has kept me alive and ticking for years, and who swiftly and confidently rejected the original diagnosis of nothing worse than pneumonia. To the surgeons, neurologists, anesthesiologists, and the perfusionist, who kept my systems going for many hours under daunting circumstances. To the dozen or so physician assistants, and to nurses and physical therapists and x-ray technicians and a small army of phlebotomists so deft that you hardly know they are drawing your blood, and the people who brought the meals, kept my room clean, did the mountains of laundry generated by such a messy case, wheel-chaired me to x-ray, and so forth. These people came from Uganda, Kenya, Liberia, Haiti, the Philippines, Croatia, Russia, China, Korea, India—and the United States, of course—and I have never seen more impressive mutual respect, as they helped each other out and checked each other's work. But for all their teamwork, this local gang could not have done their jobs without the huge background of contributions from others. I remember with gratitude my late friend and Tufts colleague, physicist Allan Cormack, who shared the Nobel Prize for his invention of the c-t scanner. Allan—you have posthumously saved yet another life, but who's counting? The world is better for the work you did. Thank goodness. Then there is the whole system of medicine, both the science and the technology, without which the best-intentioned efforts of individuals would be roughly useless. So I am grateful to the editorial boards and referees, past and present, of Science, Nature, Journal of the American Medical Association, Lancet, and all the other institutions of science and medicine that keep churning out improvements, detecting and correcting flaws.

Do I worship modern medicine? Is science my religion? Not at all; there is no aspect of modern medicine or science that I would exempt from the most rigorous scrutiny, and I can readily identify a host of serious problems that still need to be fixed. That's easy to do, of course, because the worlds of medicine and science are already engaged in the most obsessive, intensive, and humble self-assessments yet known to human institutions, and they regularly make public the results of their self-examinations. Moreover, this open-ended rational criticism, imperfect as it is, is the secret of the astounding success of these human enterprises. There are measurable improvements every day. Had I had my blasted aorta a decade ago, there would have been no prayer of saving me. It's hardly routine today, but the odds of my survival were actually not so bad (these days, roughly 33 percent of aortic dissection patients die in the first twenty-four hours after onset without treatment, and the odds get worse by the hour thereafter).

One thing in particular struck me when I compared the medical world on which my life now depended with the religious institutions I have been studying so intensively in recent years. One of the gentler, more supportive themes to be found in every religion (so far as I know) is the idea that what really matters is what is in your heart: if you have good intentions, and are trying to do what (God says) is right, that is all anyone can ask. Not so in medicine! If you are wrong—especially if you should have known better—your good intentions count for almost nothing. And whereas taking a leap of faith and acting without further scrutiny of one's options is often celebrated by religions, it is considered a grave sin in medicine. A doctor whose devout faith in his personal revelations about how to treat aortic aneurysm led him to engage in untested trials with human patients would be severely reprimanded if not driven out of medicine altogether. There are exceptions, of course. A few swashbuckling, risk-taking pioneers are tolerated and (if they prove to be right) eventually honored, but they can exist only as rare exceptions to the ideal of the methodical investigator who scrupulously rules out alternative theories before putting his own into practice. Good intentions and inspiration are simply not enough.

In other words, whereas religions may serve a benign purpose by letting many people feel comfortable with the level of morality they themselves can attain, no religion holds its members to the high standards of moral responsibility that the secular world of science and medicine does! And I'm not just talking about the standards 'at the top'—among the surgeons and doctors who make life or death decisions every day. I'm talking about the standards of conscientiousness endorsed by the lab technicians and meal preparers, too. This tradition puts its faith in the unlimited application of reason and empirical inquiry, checking and re-checking, and getting in the habit of asking "What if I'm wrong?" Appeals to faith or membership are never tolerated. Imagine the reception a scientist would get if he tried to suggest that others couldn't replicate his results because they just didn't share the faith of the people in his lab! And, to return to my main point, it is the goodness of this tradition of reason and open inquiry that I thank for my being alive today.

What, though, do I say to those of my religious friends (and yes, I have quite a few religious friends) who have had the courage and honesty to tell me that they have been praying for me? I have gladly forgiven them, for there are few circumstances more frustrating than not being able to help a loved one in any more direct way. I confess to regretting that I could not pray (sincerely) for my friends and family in time of need, so I appreciate the urge, however clearly I recognize its futility. I translate my religious friends' remarks readily enough into one version or another of what my fellow brights have been telling me: "I've been thinking about you, and wishing with all my heart [another ineffective but irresistible self-indulgence] that you come through this OK." The fact that these dear friends have been thinking of me in this way, and have taken an effort to let me know, is in itself, without any need for a supernatural supplement, a wonderful tonic. These messages from my family and from friends around the world have been literally heart-warming in my case, and I am grateful for the boost in morale (to truly manic heights, I fear!) that it has produced in me. But I am not joking when I say that I have had to forgive my friends who said that they were praying for me. I have resisted the temptation to respond "Thanks, I appreciate it, but did you also sacrifice a goat?" I feel about this the same way I would feel if one of them said "I just paid a voodoo doctor to cast a spell for your health." What a gullible waste of money that could have been spent on more important projects! Don't expect me to be grateful, or even indifferent. I do appreciate the affection and generosity of spirit that motivated you, but wish you had found a more reasonable way of expressing it.

But isn't this awfully harsh? Surely it does the world no harm if those who can honestly do so pray for me! No, I'm not at all sure about that. For one thing, if they really wanted to do something useful, they could devote their prayer time and energy to some pressing project that they can do something about. For another, we now have quite solid grounds (e.g., the recently released Benson study at Harvard) for believing that intercessory prayer simply doesn't work. Anybody whose practice shrugs off that research is subtly undermining respect for the very goodness I am thanking. If you insist on keeping the myth of the effectiveness of prayer alive, you owe the rest of us a justification in the face of the evidence. Pending such a justification, I will excuse you for indulging in your tradition; I know how comforting tradition can be. But I want you to recognize that what you are doing is morally problematic at best. If you would even consider filing a malpractice suit against a doctor who made a mistake in treating you, or suing a pharmaceutical company that didn't conduct all the proper control tests before selling you a drug that harmed you, you must acknowledge your tacit appreciation of the high standards of rational inquiry to which the medical world holds itself, and yet you continue to indulge in a practice for which there is no known rational justification at all, and take yourself to be actually making a contribution. (Try to imagine your outrage if a pharmaceutical company responded to your suit by blithely replying "But we prayed good and hard for the success of the drug! What more do you want?")

The best thing about saying thank goodness in place of thank God is that there really are lots of ways of repaying your debt to goodness—by setting out to create more of it, for the benefit of those to come. Goodness comes in many forms, not just medicine and science. Thank goodness for the music of, say, Randy Newman, which could not exist without all those wonderful pianos and recording studios, to say nothing of the musical contributions of every great composer from Bach through Wagner to Scott Joplin and the Beatles. Thank goodness for fresh drinking water in the tap, and food on our table. Thank goodness for fair elections and truthful journalism. If you want to express your gratitude to goodness, you can plant a tree, feed an orphan, buy books for schoolgirls in the Islamic world, or contribute in thousands of other ways to the manifest improvement of life on this planet now and in the near future.

Or you can thank God—but the very idea of repaying God is ludicrous. What could an omniscient, omnipotent Being (the Man Who has Everything?) do with any paltry repayments from you? (And besides, according to the Christian tradition God has already redeemed the debt for all time, by sacrificing his own son. Try to repay that loan!) Yes, I know, those themes are not to be understood literally; they are symbolic. I grant it, but then the idea that by thanking God you are actually doing some good has got to be understood to be just symbolic, too. I prefer real good to symbolic good.

Still, I excuse those who pray for me. I see them as like tenacious scientists who resist the evidence for theories they don't like long after a graceful concession would have been the appropriate response. I applaud you for your loyalty to your own position—but remember: loyalty to tradition is not enough. You've got to keep asking yourself: What if I'm wrong? In the long run, I think religious people can be asked to live up to the same moral standards as secular people in science and medicine.

DANIEL C. DENNETT is University Professor, Professor of Philosophy, and Director of the Center for Cognitive Studies at Tufts University. His most recent book is Breaking the Spell: Religion as a Natural Phenomenon.

See also: The Brights


While I have sometimes found myself disagreeing rather vehemently with Daniel Dennett, in this case I think he is absolutely right on. I had a somewhat similar experience last month - I was rushed to the hospital with my right ureter blocked by a HUGE kidney stone. It was extraordinarily painful, and was causing my right kidney to swell, and would probably have eventually caused it to die, with me following not long after. But, with the help of the ER staffs in two hospitals, an ambulance crew who drove me from the little town of Howell, Michigan to the University of Michigan Hospital, and my urologist and the surgical staff at my home hospital here in Ithaca, I am now much better. Anyway, while I lay there in a drug-induced haze (dilaudid, a morphine analog), I too mused on the question of prayer and the efficacy of religious belief versus "belief" in the protocols and practices of modern medicine (which is, of course, entirely based on the empirical sciences), and concluded just what Daniel Dennett did: that I would much rather have an atheist medical doctor, well trained in medical science, operating on me than a deeply religious person without such training.

Don't get me wrong: I don't begrudge religious believers their beliefs. But, if I had to make a choice and my life (or the life of someone I loved) were on the line, I would choose science every time. In other words, if it were a choice between a deeply religious but poorly trained doctor without much "bedside manner" and an atheist but highly trained doctor with the bedside manner of a Marine drill sargeant, I would choose the latter every time.

And would I appreciate anyone praying for me? I would of course appreciate the sentiment, but would not expect it to have any effect whatsoever on the outcome. Unlike science, prayer has no observable effect on the course of events in the real, physical world...which is, as far as I know, the only world there is.


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Wednesday, November 08, 2006

Deborah Owens Fink Defeated in Ohio School Board Race

SOURCE: Evolution in Ohio Board of Education Races

COMMENTARY: Allen MacNeill

First, the news story, compliments of the National Center for Science Education (commentary follows):

In a closely watched race, Tom Sawyer handily defeated incumbent Deborah Owens-Fink for the District 7 seat on the Ohio state board of education. Evolution education was a key issue in the race; on the board, Owens-Fink consistently supported antievolution measures, including the "Critical Analysis of Evolution" model lesson plan, which was rescinded by the board in February 2006, and dismissed the National Academy of Sciences as "a group of so-called scientists." Defending her stance to The New York Times (October 26, 2006), she described the idea that there is a scientific consensus on evolution as "laughable."

Sawyer, in contrast, told the Akron Beacon-Journal (October 23, 2006) that evolution is "grounded in numerous basic sciences and is itself a foundational life science. By contrast, creationism in its many forms is not science but theology." But the campaign was not solely about evolution, he subsequently explained to the Beacon-Journal (November 8, 2006): the evolution debate "was a metaphor for the failure of some members of the state board of education to understand the larger issues facing education in Ohio. I mean funding, quality and governance."

Owens-Fink and Sawyer aired their views during a radio discussion entitled "Evolution's Effect on Voters," broadcast on October 26, 2006, by WCPN, and available on-line in MP3 format; also on the show were "intelligent design" sympathizer Chris Williams and Brown University cell biologist Kenneth Miller, then stumping for Sawyer and other pro-evolution-education state board of education candidates in Ohio. (A high point occurred when Williams claimed that evolution delayed the discovery of small interfering RNA, and Miller replied by remarking that Craig Mello, who won a Nobel Prize in 2006 for his work on RNA interference, was a student in the first biology class he taught.)

In the four-way race, Sawyer received 54% of the vote to Owens-Fink's 29%, David Kovacs's 12%, and John Jones's 9%, according to the Associated Press. The Beacon-Journal reports that Owens-Fink's campaign spent over $100,000, while Sawyer's spent about $50,000 -- both "unusually large sums for a state school board race." Sawyer also enjoyed the support of the pro-science-education coalition Help Ohio Public Education, organized by Lawrence M. Krauss and Patricia Princehouse at Case Western Reserve University and Steve Rissing at the Ohio State University.

Pro-science candidates prevailed elsewhere in Ohio. In District 4, incumbent G. R. "Sam" Schloemer handily defeated challenger John Hritz, described by the Cleveland Plain Dealer (October 22, 2006) as "a conservative millionaire who wants to include alternatives to Darwinism in science class." In District 2, John Bender narrowly triumphed in a four-way race with 37% of the vote; his closest rival, Kathleen McGarvey, who won 35% of the vote, was described by the Plain Dealer as "sympathetic to teaching alternatives to evolution." And in District 8, Deborah L. Cain defeated incumbent Jim Craig, who was criticized for ambivalence about the "critical analysis" effort.

The result of Ohio's gubernatorial election is also relevant, since eight seats on the state board of education are filled by gubernatorial appointment. Responding to a question from the Columbus Dispatch (July 23, 2006), Democrat Ted Strickland said, "Science ought to be taught in our classrooms. Intelligent design should not be taught as science," while Republican Ken Blackwell said, "I believe in intelligent design, and I believe that it should be taught in schools as an elective," adding, "And I don't see it as having met the generally accepted criteria as a science." Strickland won in the November 7, 2006, election, with 60% of the vote.


About a week ago, I posted a commentary on the election race for the Ohio state board of education, highlighting the opinions and positions of ID supporter and anti-evolutionist, Deborah Owens Fink (see Scientists Endorse Candidate Over Teaching of Evolution. As the foregoing news story indicates, Owens Fink was overwhelmingly defeated yesterday by her pro-science rival, Tom Sawyer, in a closely watched election in a state that has repeatedly been a battleground over the teaching of evolution in the public schools.

In addition to Owens Fink, three other anti-evolution candidates for the Ohio school board were also defeated, in what appears to be a landslide in favor of the teaching of the science of evolution in the public schools (see "Honest Science Wins in Ohio" for the details). Following on the heels of the Kitzmiller v. Dover decision last December and similar court cases nationwide, it looks like ID is in full retreat in states that were once touted by the Discovery Institute as key to the success of ID in the public schools.

Even more interesting in the context of yesterday's elections is the fact that public support for the teaching of evolution (and against ID) cut across party lines in Ohio. The pro-evolution winners in the Ohio school board elections included both Democrats and Republicans, indicating decisively that support for good science (and opposition to pseudoscience) is a non-partisan issue. Even in states in which the voting public is generally conservative, such as Ohio, there is a landslide going on, a landslide in favor of science as it is practiced and taught by working scientists.

The "politics and public relations" tactics of the Discovery Institute have been consistently losing nationwide for almost a year, and public opposition to their deliberate distortions of science and scientific research has been growing exponentially. Even more encouraging to scientists and their supporters is the fact, demonstrated most clearly in Ohio yesterday, that even with massive amounts of money for political advertisements and public relations, the Discovery Institute is losing, and losing overwhelmingly in states once considered their best and brightest hope for ID in the public schools.

So, the future looks bright for real science – as I have said before, it's a wonderful time to be an evolutionary biologist, and an even more wonderful time to teach evolutionary biology!


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Wednesday, November 01, 2006

An Evolutionary Theory Of Right And Wrong

AUTHOR: Nicholas Wade

SOURCE: An Evolutionary Theory Of Right And Wrong

COMMENTARY: Allen MacNeill

Just in time, here is a review of a new book on the subject of the relationship between evolution and ethics/morals. Those of you who are currently students in evolution at Cornell will already be familiar with this topic: Essay #3 asks you to focus your attention on the very same question. Does knowing that our evolutionary past may strongly bias us in the direction of increased sociality have anything at all to do with answering the question "how should we behave?" Read the book review, and then meet me following it for my own opinion:


Who doesn’t know the difference between right and wrong? Yet that essential knowledge, generally assumed to come from parental teaching or religious or legal instruction, could turn out to have a quite different origin.

Primatologists like Frans de Waal have long argued that the roots of human morality are evident in social animals like apes and monkeys. The animals’ feelings of empathy and expectations of reciprocity are essential behaviors for mammalian group living and can be regarded as a counterpart of human morality.

Marc D. Hauser, a Harvard biologist, has built on this idea to propose that people are born with a moral grammar wired into their neural circuits by evolution. In a new book, “Moral Minds” (HarperCollins 2006), he argues that the grammar generates instant moral judgments which, in part because of the quick decisions that must be made in life-or-death situations, are inaccessible to the conscious mind.

People are generally unaware of this process because the mind is adept at coming up with plausible rationalizations for why it arrived at a decision generated subconsciously.

Dr. Hauser presents his argument as a hypothesis to be proved, not as an established fact. But it is an idea that he roots in solid ground, including his own and others’ work with primates and in empirical results derived by moral philosophers.

The proposal, if true, would have far-reaching consequences. It implies that parents and teachers are not teaching children the rules of correct behavior from scratch but are, at best, giving shape to an innate behavior. And it suggests that religions are not the source of moral codes but, rather, social enforcers of instinctive moral behavior.

Both atheists and people belonging to a wide range of faiths make the same moral judgments, Dr. Hauser writes, implying “that the system that unconsciously generates moral judgments is immune to religious doctrine.” Dr. Hauser argues that the moral grammar operates in much the same way as the universal grammar proposed by the linguist Noam Chomsky as the innate neural machinery for language. The universal grammar is a system of rules for generating syntax and vocabulary but does not specify any particular language. That is supplied by the culture in which a child grows up.

The moral grammar too, in Dr. Hauser’s view, is a system for generating moral behavior and not a list of specific rules. It constrains human behavior so tightly that many rules are in fact the same or very similar in every society — do as you would be done by; care for children and the weak; don’t kill; avoid adultery and incest; don’t cheat, steal or lie.

But it also allows for variations, since cultures can assign different weights to the elements of the grammar’s calculations. Thus one society may ban abortion, another may see infanticide as a moral duty in certain circumstances. Or as Kipling observed, “The wildest dreams of Kew are the facts of Katmandu, and the crimes of Clapham chaste in Martaban.”

Matters of right and wrong have long been the province of moral philosophers and ethicists. Dr. Hauser’s proposal is an attempt to claim the subject for science, in particular for evolutionary biology. The moral grammar evolved, he believes, because restraints on behavior are required for social living and have been favored by natural selection because of their survival value.

Much of the present evidence for the moral grammar is indirect. Some of it comes from psychological tests of children, showing that they have an innate sense of fairness that starts to unfold at age 4. Some comes from ingenious dilemmas devised to show a subconscious moral judgment generator at work. These are known by the moral philosophers who developed them as “trolley problems.”

Suppose you are standing by a railroad track. Ahead, in a deep cutting from which no escape is possible, five people are walking on the track. You hear a train approaching. Beside you is a lever with which you can switch the train to a sidetrack. One person is walking on the sidetrack. Is it O.K. to pull the lever and save the five people, though one will die?

Most people say it is.

Assume now you are on a bridge overlooking the track. Ahead, five people on the track are at risk. You can save them by throwing down a heavy object into the path of the approaching train. One is available beside you, in the form of a fat man. Is it O.K. to push him to save the five?

Most people say no, although lives saved and lost are the same as in the first problem.

Why does the moral grammar generate such different judgments in apparently similar situations? It makes a distinction, Dr. Hauser writes, between a foreseen harm (the train killing the person on the track) and an intended harm (throwing the person in front of the train), despite the fact that the consequences are the same in either case. It also rates killing an animal as more acceptable than killing a person.

Many people cannot articulate the foreseen/intended distinction, Dr. Hauser says, a sign that it is being made at inaccessible levels of the mind. This inability challenges the general belief that moral behavior is learned. For if people cannot articulate the foreseen/intended distinction, how can they teach it?

Dr. Hauser began his research career in animal communication, working with vervet monkeys in Kenya and with birds. He is the author of a standard textbook on the subject, “The Evolution of Communication.” He began to take an interest in the human animal in 1992 after psychologists devised experiments that allowed one to infer what babies are thinking. He found he could repeat many of these experiments in cotton-top tamarins, allowing the cognitive capacities of infants to be set in an evolutionary framework.

His proposal of a moral grammar emerges from a collaboration with Dr. Chomsky, who had taken an interest in Dr. Hauser’s ideas about animal communication. In 2002 they wrote, with Dr. Tecumseh Fitch, an unusual article arguing that the faculty of language must have developed as an adaptation of some neural system possessed by animals, perhaps one used in navigation. From this interaction Dr. Hauser developed the idea that moral behavior, like language behavior, is acquired with the help of an innate set of rules that unfolds early in a child’s development.

Social animals, he believes, possess the rudiments of a moral system in that they can recognize cheating or deviations from expected behavior. But they generally lack the psychological mechanisms on which the pervasive reciprocity of human society is based, like the ability to remember bad behavior, quantify its costs, recall prior interactions with an individual and punish offenders. “Lions cooperate on the hunt, but there is no punishment for laggards,” Dr. Hauser said.

The moral grammar now universal among people presumably evolved to its final shape during the hunter-gatherer phase of the human past, before the dispersal from the ancestral homeland in northeast Africa some 50,000 years ago. This may be why events before our eyes carry far greater moral weight than happenings far away, Dr. Hauser believes, since in those days one never had to care about people remote from one’s environment.

Dr. Hauser believes that the moral grammar may have evolved through the evolutionary mechanism known as group selection. A group bound by altruism toward its members and rigorous discouragement of cheaters would be more likely to prevail over a less cohesive society, so genes for moral grammar would become more common.

Many evolutionary biologists frown on the idea of group selection, noting that genes cannot become more frequent unless they benefit the individual who carries them, and a person who contributes altruistically to people not related to him will reduce his own fitness and leave fewer offspring.

But though group selection has not been proved to occur in animals, Dr. Hauser believes that it may have operated in people because of their greater social conformity and willingness to punish or ostracize those who disobey moral codes.

“That permits strong group cohesion you don’t see in other animals, which may make for group selection,” he said.

His proposal for an innate moral grammar, if people pay attention to it, could ruffle many feathers. His fellow biologists may raise eyebrows at proposing such a big idea when much of the supporting evidence has yet to be acquired. Moral philosophers may not welcome a biologist’s bid to annex their turf, despite Dr. Hauser’s expressed desire to collaborate with them.

Nevertheless, researchers’ idea of a good hypothesis is one that generates interesting and testable predictions. By this criterion, the proposal of an innate moral grammar seems unlikely to disappoint.


So, do you think that we have an innate predisposition (inherited from our primate ancestors) to behave in ways we would recognize as "moral?" I think so, and so apparently do Franz De Waal and Marc Hauser (not to mention E. O. Wilson, Jane Goodall, and a host of other evolutionary biologists).

But, does it therefore follow that this predisposition necessarily dictates how we should behave? I believe that the answer to this question is no. More than that, I believe that to make the jump from the former to the latter is to commit a fundamental logical fallacy (indeed, it has a formal name - the "naturalistic fallacy"). It conflates statements about what "is" the case (i.e. what is "natural" behavior for us and our fellow primates) and what "ought" to be the case. This fallacy was pointed out a century ago, most forcefully by G. E. Moore, who pointed out that "is" statements cannot logically be made equivalent to "ought" statements.

This distinction is crucially important, and nowhere more so than in the application of evolutionary theory to human behavior. The economic and social movement known as "social darwinism" was fundamentally based on the "naturalistic fallacy," as exemplified by the words of the well-known English hymn, "All Things Bright And Beautiful," written by Cecil Frances Humphreys Alexander:

All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

All well and good, but here's the next verse:

The rich man in his castle,
The poor man at his gate,
God made them, high or lowly,
And ordered their estate.

(Interestingly, if you do a Google search for these particular lyrics, you will not find them. Apparently, the social darwinist overtones of the second verse do not sit well with modern audiences, including those in church.)

Alexander was most emphatically not a "social darwinist," yet the moral equation presented in his hymn is essentially equivalent to that of Herbert Spencer and the other social darwinists: that one's position in life (and, by implication, one's behavior) are determined by a force outside one's self (God or natural selection), and that all that remains for us is to "get with the program."

In a word: bullshit. That way lies the gas chambers at Auschwitz. No amount of science can tell us what we ought to do. At most, scientific knowledge can tell us how difficult (or easy) what we ought to do might be, but to conflate the two is to commit both a logical fallacy and monstrous evil. I sincerely hope that most evolutionary biologists will not agree with either the opinions of Marc Hauser or Franz De Waal on this subject, no matter how encouraging they may be. Long and hard experience has shown us that the "naturalistic fallacy" can be used to justify monstrous injustices (as has the belief in the authority of a "supernatural lawgiver," and for the same reason).

As adults, we must face up to the difficult responsibility of deciding what we "ought" to do, and then do it, no matter how easy or difficult. If it is the former (and if this is because of our evolutionary heritage), then perhaps the road ahead will not be as rocky as the one we have trod to get here. However, if it is the latter (and I suspect it may be, once again based on my understanding of our evolutionary heritage - more on this later), then that's just tough: but (to paraphrase Charles Darwin), one must do one's duty.


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