Thursday, January 2, 2014

Humans and flowering plants

In the last post I referred you to a paper on flowering plants and the apparent gateway mutation, genetic doubling, that allowed for its emergence.  It seems that great apes, including us, were products of a similar genetic oddity, at least if some current reported research is to be believed (here). It appears that something (possibly some over excited virus) spread extra genes across "their resident chromosomes like dandelions across a lawn" and this resulted in new genes resulting in increased brain size and development. Interestingly, these "duplicons" are thought to be both important and understudied and, of course, just our luck, very hard to study using "the most efficient methods" currently available for studying genetic sequences. Evan  Eichler, one of the leading researchers on this topic, notes that a duplicons seem to create an "extremely unstable genetic element that provides a template for evolutionary change." Note the word 'template.' First the genetic change creating new opportunities for change then selection given these novel options. Sounds a little like the logic of UG, doesn't it (heh, heh). Here's a quote that is music to the ears of Rationalists like me (from Philip Hastings): "It's possible that we are the way we are largely because of  this mechanism that generates dramatic episodes of chromosomal structural change" (my emphasis, NH). This is evolution, not via selection, but dramatic mutation. Of course, selection matters, but the interesting changes seem linked to such dramatic and far reaching gateway genetic changes that allow for phenotypic novelty. Natural selection, in other words, works against the background of options afforded by these structural genetic novelties. These appeared to develop pretty rapidly with different effects in different Apes. Curiously, these guys have no trouble conceiving of the possibility that something like this lies behind our unique capacities Why are we the way we are? Genetic accident! The shaping effects of natural selection? Maybe, but at least for these guys, that's not where they see the real action.

Chomsky likes to note that for chemistry to unify with physics, we needed a whole new conception of physics. Maybe to understand how human cognitive capacities could have evolved we will need a whole new conception of evolution and its attendant mechanisms. We look to shaping effects of the environment early on in our biological and psychological investigations, for these are easy to spot and track. We can say interesting things about environmental influences and spin fancy stories about how this could have happened in response to some external stimulus.  The idea that some virus spread genetic dust in our chromosomes and this resulted in the great leap forward seems like so much magic. But then again, is it really any worse than action at a distance or 12-dimensional space time or superpositions? But that's the way it is. Why not in our little domains as well?

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