Olivia Judson wrote a blog post on her NYTimes blog that has many people rattled. Why? Because she used the term "Hopeful Monster" and this term makes many biologists go berserk, foaming at the mouth. And they will not, with their eye-sight fogged by rage, notice her disclaimer:
Note, however, that few modern biologists use the term. Instead, most people speak of large morphological changes due to mutations acting on single genes that influence embryonic development.
So, was Olivia Judson right or wrong in her article? Both. Essentially she is correct, but she picked some bad examples, overgeneralized a bit, over-reached a little and she used the dreaded term that was bound to shut down all rational processes occurring in some biologists' brains. Remember that she wrote to general audience. If she took time and space to explain all the nuances and details she would have lost her audience somewhere in the middle of the second paragraph. I think that her post explains the topic just fine for the intended audience, pointing out that not all evolutionary changes take millions of years of imperceptible change - some do, indeed, happen relatively abruptly (yet it can be explained completely mechanistically, not giving Cdesign Proponentsists any hope). Not every day, but they do.
So, who jumps first into the fray with an angry rebuttal - one of the Usual Suspects: Jerry Coyne in a guest-post on The Loom:
Unfortunately, her piece is inaccurate and irresponsible, especially for a journalist with a strong science background (Judson has a doctorate from Oxford). I've admired Judson's columns and her whimsical and informative book Dr. Tatiana's Sex Advice to All Creation. But this latest posting is simply silly. As an evolutionary biologist, I'm used to seeing our field twisted out of shape to satisfy the demands of journalists who love sensational new findings--especially if they go against long-held Darwinian beliefs like the primacy of gradual, stepwise evolution. But I'm not used to seeing one of my own colleagues whip up excitement about evolutionary biology by distorting its findings.
Unfortunately, in bashing Judson along with making legitimate points (how many people will ignore this caveat in their responses?), Coyne ends up being more wrong than she is. And his intended audience is, arguably, better scientifically educated than hers - it's the Scienceblogs.com readers, not NYTimes. While bashing her head into a rock, Jerry makes visible his emotional enmity towards everybody who has a bigger picture of evolution than he has and has at their disposal both a methodological and a conceptual toolkit that Jerry lacks.
Before you jump on me, read the historical reviews of the concept of the Hopeful Monster by Brian and John. Then, read Greg and Razib who are far too lenient on Coyne but add good points of their own. Finally, read PZ Myers and especially Larry Moran for a clear explanation of the entire set of issues - the history, sources of current emotional disputes, and the current science. Reading all of these is essential to understanding the claims in this post as I do not have space/time to repeat all of their claims at length - so click on the links and read first before commenting.
In a back-and-forth with a commenter, Coyne defends himself that he is talking about the changes in genes, not evolution. This just shows his bias - he truly believes that evolution - all of it - can be explained entirely by genetics, particularly population genetics. His preferred definition of evolution is probably the genocentric nonsense like "evolution is a change of gene frequencies in a population over time". I prefer to think of it as "evolution is change in development due to ecology" (a softening of Van Valen's overly-strong definition "evolution is control of development by ecology"). Population genetics is based on the Hardy-Weinberg equilibrium - pretty much all of it is a build-on and embellishment of it. Population geneticists tend to forget, once they get into complex derivations of HW, that HW has about a dozen completely unrealistic assumptions underlying it. Now, in a case-to-case basis, some of those assumptions can be safely ignored, some can be mathematically taken care of, but some are outside of the scope of mathematics (or at least the kind of math that can be integrated into the development of HW). Those are ignored or dismissed and, if this is pointed out by those working on evolution from a Bigger Picture perspective, met with anger.
When Goldshmidt's book The Material Basis of Evolution was reissued, Stephen Jay Gould wrote a lengthy Introduction. About a dozen years ago I checked the book out of the library and skimmed the book itself. I read Gould's intro very carefully (I wonder if it is available somewhere online for free? Update: Gould's introduction is available online here, hat-tip to Michael Barton.). It is also worthwhile to read Gould's 1980 essay The Return of Hopeful Monsters keeping in mind that evo-devo was barely beginning at the time (yes, it is 28 years old, so do not judge it by current knowledge - put a historian's cap on when reading it).
In his Big Book, Gould wrote:
"By proposing a comprehensive formalist theory in the heyday of developing Darwinian orthodoxy, Richard Goldschmidt became the whipping boy of the Modern Synthesis--and for entirely understandable reasons. Goldschmidt showed his grasp, and his keen ability to utilize, microevolutionary theory by supporting this approach and philosophy in his work on variation and intraspecific evolution within the gypsy moth, Lymantria dispar. But he then expressed his apostasy by advocating discontinuity of causality, and proposing a largely nonselectionist and formalist account for macroevolution from the origin of species to higher levels of phyletic pattern. Goldschmidt integrated both themes of saltation (in his concept of "systemic mutation" based on his increasingly lonely, and ultimately indefensible, battle to deny the corpuscular gene) and channeling (in his more famous, if ridiculed, idea of "hopeful monsters," or macromutants channeled along viable lines set by internal pathways of ontogeny, sexual differences, etc.). The developmental theme of the "hopeful monster" (despite its inappropriate name, virtually guaranteed to inspire ridicule and opposition), based on the important concept of "rate genes," came first in Goldschmidt's thought, and always occupied more of his attention and research. Unfortunately, he bound this interesting challenge from development, a partially valid concept that could have been incorporated into a Darwinian framework as an auxiliary hypothesis (and now has been accepted, to a large extent, if under different names), to his truly oppositional and ultimately incorrect theory of systemic mutation, therefore winning anathema for his entire system. Goldschmidt may have acted as the architect of his own undoing, but much of his work should evoke sympathetic attention today."
So, Coyne's Gould-bashing, as Larry Moran demonstrated, is just petty and baseless sniping by one scientist of limited scope at another who actually "got it".
I thought the discussion so far has been far too tame. So, here is the red meat! I want to see a real fight - a blogospheric war that brings in some serious traffic, OK?
Hopeful monster? Well, in the popular sense I would hardly call it hopeful, but in any sense it is a monster. I'm speaking, of course, of Canine Transmissible Venereal Tumor (CTVT). An organism descended from a dog's tumor. A particular dog's tumor that over the course of 5,000 years of evolutionary history has given rise to not just a new species, but a new phylum at the least, and more likely a new kingdom of life.
A new type of parasitic slime mold for all intents and purposes. And calling it just a contagious cancer misses all the changes the creature's genome has gone through over the millenia. If changes in a mere 2% of a genome suffices to make for a new genus (much less a new species), then what do you expect the loss of over 50% of the original genome to do? Just because CTVT is descended from dogs doesn't make it a dog or a dog's disease.
Sometimes a small mistake early in the process means huge changes later down the line. It happens in computer code, it happens in genetic code. And sometimes that error means a big change that results in a viable product. CTVT is an obligate parasite, but in it's constrained environment it thrives and is able to colonize new terrain. For this reason I say that the original case of CTVT was a hopeful monster.
AK: There's a similar disease--a contagious cancer with karyotypic chamges--decimating Tasmanian Devils now too. To keep everything all nice & monophyletic, I s'pose that's yet another Kingdom?
Quail: How do you get a change in development at the population level without a change in allele frequencies?
My response is here
"evolution is change in development due to ecology"
So- no such thing as neutral evolution? Larry Moran is not going to be pleased...
Hmmm, one can get out of that linguistic trap, I guess, by arguing that there is always change in place, but there is directional change only if the ecology pushes it in one direction.
But couldn't you say the same for those silly popgen adherents ? There will be directional change if selection (ie the environment including all other organisms, and genes within an organism if you want to be a Dawkinsist, and the climate etc etc) favours mutations present in a population?
I tend to agree that strict genocentric interpretations of evolution miss the point, biology is more than any other science about diversity. But I don't think they are wrong, there are just different facets of evolution to investigate and different ways to go about doing that. Perhaps Coyne talking about the gradual accumulation of small changes sounds too much like 'bean bag' genetics but those changes must have been made to developmental networks and other things that the evo-devo crowd can investigate and they have been favoured for reasons evolutionary ecologists could go out and test. It's only when people start to think that their method is the ONE TRUE WAY to understand or even conceptualise evolution that we have a problem
Well, that's my 10c worth (we've done away with 1, 2 and 5 cent coins down here), I hope you get your blogwar!
Oh, and a (possibly) amusing anecdote about the different ways people go about studying evolution. The story goes that a population biologist who had been working on the spread of a simple Mendelian trait in a population of butterflies was contacted by someone who had finally mapped the trait in question to a particular gene. The population geneticist had to admit he couldn't muster any excitement about it because "I always knew it would be a gene".