The Y Chromosome. Or, Girls, and Females, and Crones; Oh My

Sumac, thanks for that Nature article.

Much more informative than the insecure self-indulgence of a female chauvinist . . .

I honestly don't know what the advantage would be. Maybe I'll be able to tell you after I take genetics, or you could probably track down farmerman and get an answer from him.

It doesn't really provide any disadvantage, because it happens after a number of cell divisions in the embryo, and so some cells have one X chromosome as the Barr body, and some have the other. This is why all calico cats are female, by the way. The different colors represent regions that arise from cells expressing a different X chromosome; the gene(s) on each chromosome responsible for color determination code for a different color, and so you end up with apparently random patches of different colors. (There is a vanishingly small chance, incidentally, that a woman with one "color-blind" chromosome and one for normal color vision would end up color blind, if every single cone in both retinae descended from cells in which the normal color-vision chromosome became Barr bodies. The odds of this actually happening are virtually zero, though.)

Honestly, though, I don't know much about it, and I'll have to refer you to someone more knowledgeable to check my facts and to offer more information.

And thanks, also, for the Nature article. A little more informative, but mostly over me head.

I'll see if I can call in farmerman. This is just too interesting not to explore it further.

Jeez, its really strange here. I got on line and it only showed me 2 topics on the board. I had to list all topics.

Patios correct in that the inactivation of one of the x (sex, not autosomal) chromosomes, is the basis for production of essnetially "clones" I have a neat little url here that has just the explanation and some more detail with graphics and a nice sequence chart. Scroll down to x inactivation

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexChromosomes.html

Sorry, only time to quickly peruse the link before I begin what threatens to be a busy and unpleasant day.

Does the fact the the paternal X chromosome is always inactivated in the extra-embryonic tissues (or whatever the placenta et al is called) somehow prevent the mother from rejecting the enitre foetus as alien? Are the genes coding for the Rhesus factor proteins housed on the sex X (sex X sex X, hee hee) chromosome or something? Or do we not know what competitive advantage the deactivation of the paternal X in these tissues might confer?

Back later. Maybe tomorrow. Cheers.

Same here, although hopefully my day will be quiet and pleasant. But I will study the link and respond later with whatever intelligent followup I can muster.

It seems intuitively correct to me, since it's something that appears in mammals (the only order where rejection of the fetus is a consideration). The Rh factor doesn't seem right, though, because that actually is a problem that evolution hasn't entirely dealt with, and (I don't think) isn't an issue throughout mammalia. And a woman can carry a fetus that isn't hers. So I'm probably way off base here.


Back to work.

Since it is always the father's X that is inactivated in female marsupials, I'd guess it had to have something to do with protecting the fetus from the mother's immune system. (But still I wonder about all those paternal autosomes. Hmmmm, again.)

Did y'all read the cool stuff in today's NYTimes about language? I'll bet wimmen started talking first. They needed to say I have a headache, Dear.

Welcome home, Kara, and welcome back to being plugged in.

Farmerman, I can't get to that article. I could get to at least the abstract if I could search by author or title.

Hmmm. So the second sentence ever invented: "You always have a headache."

PD, surely the guy came up with something wittier than that. Perhaps...."Oh. So I guess I'd better stop banging your head on that rock when you won't do what I want."

Ah, the birth of feminism. Of course, it took millennia to get passed the head-on-rock question.

Parallel to the "rocks IN head" problem!

BoGoWo is an expressionist.

yeah!
I like to go really fast.

Interesting about calicos! I knew they were always female, didn't know why. Cool.

Haven't read that article about language yet, though it's sitting at the top of the pile and beckoning to me. I should go do that now while I have the chance.

Same here, before the NYT archives it and I can't read it.