So is the second X chromosome in women supposed to be an exact copy of the first or do they differ? That's fascinating to me all by itself, and more so that some genes in the dupe can reinforce the first even though the rest of the chromosome is suppressed. EDIT: Ah, wikipedia explains that the two X chromosomes in a standard-issue woman come from the mother and paternal grandmother, and then ... "Early in embryonic…
Um the X chromosome in a women comes from the mother and the paternal grandmother and grandfather because there is crossover between X and Y chromosomes (albeit very little). There's no need to worry about the Y chromosome disappearing because it's remarkably stable. This makes sense -- males with Y mutations die out and men are extremely good at producing offspring. This only good Y chromosomes are passed on. Nevert…
If that were to occur, we'd get into more X-SRY X-SRY situations much more often though, right? Sounds unhealthy, I'd prefer to keep the Y separate and intact for as long as possible. :)