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Date: | Sun, 15 Oct 2023 19:09:49 -0400 |
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< ...if we can't yet define what is a species or a subspecies is how can we confidently make projections about whether, "species belonging to a larger genus should also include more subspecies?">
A snippet from the sidelines here regarding all this off topic Darwin/species/subspecies stuff. I don't think we can... Of course we know Darwin knew nothing about genetics and indeed, here we are all these decades later just beginning to unravel all this molecular physics. But we might be able to agree the molecular stuff has brought us a little closer to what's what and who's related to who. (for now, let's just ignore the fact that humans have genes in common with starfish and fruit flies). So the big picture from out on Pluto more than backs up Darwin's idea.
But speaking of "subspecies" for fruit flies, estimates vary anywhere from a few hundred to over 4000 depending upon who the "authority" is. And speaking of mechanisms of variation in fruit flies, these organisms have a gene known as Dscam which with its 95 variable exons utilizes alternative splicing in post transcriptional processing which is capable of encoding over 38,000 distinct combinations! (from one gene!!!) However, unlike insects and worms, it is surprising that vertebrate spliceosomes seem to be incapable of negotiating pre-mRNAs containing more than only two mutually exclusive exons. Why this is may be a topic for a different message board. Maybe when we figure out how fruit flies work, we can start on honey bees... good luck with that.
(P.S. enjoying the thread)
Graveley, B.R. (2005) ‘Mutually Exclusive Splicing of the Insect Dscam Pre-mRNA Directed by Competing Intronic RNA Secondary Structures’, Cell, 123(1), pp. 65–73. Available at: https://doi.org/10.1016/j.cell.2005.07.028.
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