Hi, POI-
I was disappointed with this interview. The exercise seemed to be one of straw man-ism in the interest of plugging a book. The straw man is a caricature of modern biology- the gene for alcoholism, gene for republicanism, etc. strain. Well, after the long searches for genes associated with schizophrenia, autism, alcoholism, etc., ending with tiny-effect variants or nothing at all, all real scientists are disabused of this notion, if they ever had it. The charicature might accurate about some of the lazier precincts of journalism “Gene for PMS Found!”, but certainly not about the scientists Mr. Blumberg actually targets. The point of all these gene studies is that variants (mutants) of gene X contribute to condition Y, but this connection is rarely 100%, so necessarily there are environmental and other gene interaction effects that contribute.
The sad part was that a much more interesting topic was left untouched, which is that freaks are developmental mutations that provide us with a similar power of insight into development that gene mutations do into genes. The primary position of genes in the story of evolution is quite secure- genes are the locus of mutation, even when they are expressed in mind-bogglingly complex ways to create the organism in continual interplay with its enviroment during development and throughout life (which is, then, the subject of variation and selection). Developmental pathways may mutate, but not in heritable fashion, unless a gene is involved first (excepting extremely rare issues). Nevertheless, accidents of development, whether caused by gene mutations, rare allele interations, chemical insults, malnutrition, or other enviromental issues, are all exceedingly informative about developmental pathways- which are robust, which are fragile, how it is that a mere ~25,000 genes can encode such a complex life form as us by way of repeated re-use of the same genes, extremely complex regulation, and other such issues in the the evo-devo field.
The issue of intersex developmental accidents is a great example. Clearly the genomic program is to generate males and females. Intersex variants, if they are infertile, which I guess is the case with the runner discussed in the show, are serious errors in terms of evolution. So the question is why such variants come up so often (if they do), after selection has had millions of years to optimize the developmental process of gender in mammals. I don’t have the answer, but that would have been an interesting question to ask Mr. Blumberg. Is there a deep complexity to the pathway that has blocked more definitive gender switching systems? Is there some positive value to having minor (fertile) forms of intersex variants in the population, much like the theory about homosexuality being a side-effect of extreme femininity being positively selected for? Are humans less sexually differentiated than other species, implying a higher rate of defective intersex variants? The questions are endless, and while development is fully integrated in the evolutionary story of modern biology, so are genes. And they ain’t magic.
