Darren New <dne### [at] sanrrcom> wrote:
> Or it's less hard to combine 48 with 46 than you might think. All the data
> is there, including the tollermerines (or however you spell it) in the middle.

Just happened to stumble across the Wikipedia articles on mules and hinnys
(citing the latter here):

"A donkey has 62 chromosomes, whereas a horse has 64. Hinnies, being hybrids of
those two species, have 63 chromosomes and are sterile."

But later on the article reveals that this is an oversimplification:

"Female mules have been known to produce offspring when mated to a purebred
horse or donkey, though this is extremely uncommon."


Duh. Didn't know that horses and donkeys have different numbers of chromosomes,
too (then again, it was news to me as well that chimps and humans have).

So this makes me think that...

- mutations changing the number of chromosomes don't seem to be as uncommon as I
had thought

- with mules and hinnys being perfectly viable and typically not showing any
other defects, and even *not always* being sterile, this gives rise to the
assumption that having an odd number of chromosomes is an absolutely
non-dramatic mutation as such (why should *only* the reproductive system show
issues? and why not always?), and that the sterility is instead imposed by
other genetic mechanisms "designed" (by evolution) to separate the two gene
pools.

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