Evolving Thoughts

Blumberg is a developmental biologist who has a real grasp of the topic, is enthusiastic about it, and has a clear target in his sights. That target is sometimes misleadingly called "The Modern Synthesis", although a better term might be something like "gene centrism"; the view often expressed in words like "genes are the program that controls the development of the organism", or "genes are information about the phenotype". Rightly so, Blumberg attacks this in what starts out as an accessible argument, based initially on the developmental errors that lead to one, three or four eyes in vertebrates, which are errors of timing based on the expression or not of (among other things) the Sonic hedgehog homolog gene, or Shh.*

He traverses the past century or more of experiments on developmental errors, and shows how the notion of the gene centrists that "it's all in the genes" has effectively been abandoned, although the terminology remains and many authors still fall back into the mindset when they aren't being careful. Implications of this include the total destruction of the "nature-nurture" divide. You simply can't have genes do anything (nature) without there being an environment that triggers, delays, and generally shepherds the development of the organism. If you doubt this, by the way, consider what genes do in a fetus in a vacuum.

Thus far, engrossing and interesting. He then moves into sex determination, covering everything from fishes that swap sexes serially to intersex children among humans, and the lack of total control by any single set of causes. But here the message of the book starts to move away from the initial target a bit, and it becomes technical, with apologies for the acronyms appearing in the body of the text. While anyone who has an acquaintance with biology will cope, the ordinary reader who is not scientifically aware may struggle. It's not a complete obstacle, but it is guaranteed to reduce the audience of this crucial message.

And the message itself struck me as left in the air a bit - something I am especially attuned to as I do it myself so often. There is a deep and important implication of the developmentalist challenge to gene centrism: taxonomic entities like races, genders, species and other groups of organisms simply lack a genetic "essence". Blumberg didn't bring that out. Maybe he has other concerns, but I would love to have seen a chapter on that.

These quibbles aside, I do recommend this book for the science enthusiast, the undergraduate science student, medical professionals, conservationists and so on. It is a good entré into a field that is resurging even as the molecular hegemony seems to have carried all before it.

* In technical papers, the gene is always written in italics, and the product of the gene, a protein which often has the same name, is written in roman text: Shh.