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by jessaustin 4432 days ago
My reading of that statement would be that the presence of the hypothesized "new gene" would produce a male while its absence would produce a female. After all, that's how SRY works, which it is hypothesized to replace. Presumably this new gene would code for a very similar set of proteins to that coded by SRY.

ISTM that there must have been some period during which both the new gene and SRY were present in the breeding population, and the inheritance of either (or both) would have produced a male. Since we're talking about fairly small populations on these islands, it was just luck that caused SRY to disappear before the new gene. I doubt we'll see this occur in larger, more-geographically-distributed populations.
1 comments
Locke1689 4432 days ago
But wouldn't that just make whatever chromosome carries this gene the new allosome? I was reading the statement as SRY moves to an autosome and then some other process regulates expression.

FWIW, biology was the one science course I never took, so I have no idea what I'm talking about.

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jessaustin 4432 days ago
But wouldn't that just make whatever chromosome carries this gene the new allosome?

Haha, maybe so, I guess that's a matter of definitions...

I was reading the statement as SRY moves to an autosome and then some other process regulates expression.

SRY translocation is not unheard-of (cf. SRY-positive 46,XX testicular "disorder"), but that's not what Prof. Kuroiwa is saying. He's talking about a change that allows a different gene to code the same proteins that SRY codes. That change could be to the gene in question, or to something else that governs how it is expressed. There's a whole family of genes (SOX) that exist all over, on both allosomes and autosomes, which are similar to SRY, and one would imagine these might substitute for it. Looking around a bit more, I find wikipedia links to a paper [0] that claims the substitute SRY is actually a group of multiple genes on X, which group of genes did translocate from Y. Fascinating stuff!

[0] http://www.ncbi.nlm.nih.gov/pubmed/12900579

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