Genetics of speciation

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RPM points out that the most recent issue of Heredity tackles the issue of the genetics of speciation. Here’s an interesting thing I’ve noted, there are two ways to look at species questions. First, there are the taxonomists, who have been strongly influenced by the cladist revolution. They take a big picture philosophical view, and are obviously greatly concerned with process in terms of classification and demarcation. In contrast, there are the evolutionary geneticists who tend to be less interested in species qua species, as opposed to the process of genetic differentiation. In other words, for the latter camp species discussions are simply an ends toward elucidating the evolutionary dynamics of populations. The taxonomists in contrast are focused on species as the ends for generating their systems of evolutionary relationships. The Neandertal introgression story should make it clear I’m interested in the dynamics of evolutionary processes, not any rigorous species classification.

Addendum: Check out this review of Henry Gee’s In Search of Deep Time: Beyond the Fossil Record to a New History of Life, to see what I mean about the taxonomic sensibility. A friend of mine recalls observing a woman in her lab being upbraided by a cladist at an entomological conference for practicing “un-Popperian” science.

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5 Comments

  1. “Genetic differentiation” leads to speciation, but the taxonomist’s goal is to ascertain how and when an actual speciation event has occurred (even in cases where reproductive isolating mechanisms have not yet completely evolved). It seems that your favored approach, “elucidating the evolutionary dynamics of populations” must eventually answer that question in the same way as the taxonomists, no?

  2. It seems that your favored approach, “elucidating the evolutionary dynamics of populations” must eventually answer that question in the same way as the taxonomists, no? 
     
    sure. but let me put it this way, i don’t care too much about ‘species concepts,’ let me just look at genetic distance metrics. who cares if post or prezygotic barriers have evolved, wuz the selection parameters (or stochastic dynamics) which resulted in these barriers?

  3. Ok, but I don’t quite see how you can say “who cares if post or prezygotic barriers have evolved” and still be interested in “the selection parameters (or stochastic dynamics) which resulted in these barriers.” (And it seems to me the authors of the papers u link to are equally interested in both questions, almost necessarily so.)

  4. (And it seems to me the authors of the papers u link to are equally interested in both questions, almost necessarily so.) 
     
    well, orr (with coyne) gives a lot of weight to BSC (ergo, mayr) in speciation. that’s pretty much a no-no from what i know of cladists. i’m not saying taxonomy isn’t interested, i’m pointing out that the core questions of interest often differ.

  5. When I first heard of the idea of taxonomy by clads it seemed to me to be brilliant. But later I read a book which pointed out that following cladism there shouldn’t be categories like reptiles (since iguanas are more closely related to us than to turtles) or fish (since mudskippers are more closely related to us than they are to tuna).  
    The point was to argue that it’s proper not to classify humans as apes, even though we’re clearly more closely related to chimps than chimps are to orangutans, and probably closer than chimps are to gorillas. Clades are great if you take it as axiomatic that taxonomy should reflect ancestry, but if you think taxonomy should indicate salient features of the species, clades just don’t cut it. 
     
    I should mention that about half the book was stab-yourslef-in-the-forehead-with-a-fork-while-you’re-eating stupid.

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