Treat selection equally

1 minute read

Massimo Pigliucci gives a combative review of Michael Lynch's new book, The Origins of Genome Architecture. A short passage lauding the books first 12 chapters says that you should buy the book:

But before we get to the controversy, let me say that the book's first 12 chapters are a mustread for anyone interested in the evolution of genomes. This Origins represents a serious, valiant, and highly scholarly attempt at making sense of the new data provided by the genomic revolution. To that aim, Lynch deploys the full array of conceptual tools that make up the modern synthesis paradigm in evolutionary biology.

And then Piglucci engages with Lynch's final chapter, in which Lynch advocates a path for future research in evolutionary biology. Lynch built a long record of accomplishments in population dynamics, ecology, and conservation biology before he turned to genomics in the past decade. He is probably best known for emphasizing the importance of demographic constraints on genome evolution and variability -- for instance, the constraint on the strength of selection against weakly deleterious variants in vertebrates compared to vastly huger microbial populations. Pigliucci reads him as advocating a strongly transmission-centric view of genome evolution:

Lynch's thesis, as mentioned above, is that the theoretical apparatus of evolutionary theory is complete and that people should stop whining about missing pieces and the need for a new synthesis: just study your population genetics and everything will be all right.
This is, of course, a perfectly respectable opinion--although the repeated, if oblique, parallels Lynch draws between legitimate scientific opponents of his view and creationists who advocate intelligent design become increasingly irritating by the end of the chapter. Lynch, however, seems convinced that all that evolutionary theory has to explain is changes in allelic frequencies within populations. If that were indeed the case, the job is done, and we are now left with simply systematizing the huge amounts of information coming forth from genomic studies. As Carroll complains [in (8), quoted by Lynch], this is a rather uninspiring theme.

I like the clarity of casting this as a disagreement between Lynch -- advocating a view of evolution dominated by transmission genetics -- and Carroll, advocating a view dominated by form. But in the end it comes back to the old "bean-bag genetics" complaint, that studying the change in gene frequencies cannot itself test hypotheses about the distribution of morphological and developmental patterns