SilverBoat -> RE: Where does gender come from? (12/28/2011 8:42:39 PM)
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ORIGINAL: vincentML quote:
Sure, two 'identical' twins might start with exactly the same DNA in their first cell, but that doesn't guarantee one or more single-base mutations immediately afterward, that even the finest sieves might not yet have discovered, I would suggest that no matter when the mutation occured in the blastula or after the twins parted, a mutation is still a genetic event. There is no evidence in this case of any difference in the uterine environment that could plausably be tied to a causal event for selective gender identity. quote:
or that some environmental factor, including their sibling's presence, could have influenced their physical development. And that 'physical' development includes the geometry and chemistry of their brains, not just their bodies. The only evidence we have is that Nicole recognized early on that she was female-gendered. Nothing in the article spoke of differences in the home environment or of the brain. Alas, we are left to speculate until we have better information. There are examples from other species (rodents, cats, dogs at least, if memory serves) that embryos influence each others' development in utero, in particular, which of the siblings turns out to be the social 'alpha' of otherwise genetic twins. I don't recall all the details, but being a step or few ahead at the earliest differentiation was thought to be significant. The mechanism proposed was hormonal releases and their effects on the other embryos' expression, chemical gradients, etc, but I don't recall the author or journal. (The article was at least a couple of years ago, I tend to keep up more with physics than biology.) I think that's sufficient to anticipate similar effects on human psychosocial phenomena, that may have as yet otherwise unexplained neurocognitive basis. If I notice or recall more of interest on that topic, I'll try to remember to add it here. quote:
ORIGINAL: tweakabelle From where I sit, the concept of 'emergent' phenomena is an exciting development. It promises huge potential as an explanatory tool. It moves the discussion beyond the barren terrain of the tedious Nature vs Nurture debate. It makes the crude deterministic perspectives - be they social, genetic/biological or genital determinism - obsolete. Regrettably, it's emergent phenomena in the physical sciences, not the neurobiology fields, and the adjunct issue of how human memetics affects even the concepts we use to think and talk about such matters, that I've sort of had to pick and choose as topics of interest. There is just so much going on in research that keeping up with everything seems impossible. Mass and forces as emergent properties of p-dimensional brane-theory, yeah, that'd be something, but probably off-topic here. Maybe a better example is hurricanes; just about everybody's focus is on tracking the 'eye' of the storm, but it's really an emergent vortex, a temporary 'eddy' that appears in a very complex process, with its location influenced by steering currents, adjacent convective potential, etc. While everybody else is looking at predictions for the eye's movement, the weatherguys (and I) are looking at where the nearby hot water and moist air will be, and the jet stream and other high/low pressure areas will be, because the center will be dragged tangent to the biggest thunderstorms that it triggers around itself. (And I tried to keep that simple, LOL.) Consciousness, identity, cognition, internal narrative, etc ... There's been lots written about those in more or less scientific and/or speculative literature, and much of that so handicapped by its own memetic bases and academic one-upmanship that it's pretty much garbage. I expect that when humans finally do explain their own consciousness, it'll be some sort of dynamic emergent, a complex neurochemical polymodal wavefront that resonates in variably multipath echoes along our synaptic geometries. And in that context, it wouldn't take much of a shift or hitch to induce a slightly different resonance, and a resulting change in worldview, identity, etc. And with all that resonating going on, it's no wonder that brained creatures need sleep, to let the busiest synapses recover, or that they dream, if not everything stays shut down ... Anyway, that's enough fun ideas for now, I need to go work on some verse that's been left untended ... Thanks for prompting some very interesting discussion! SB
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