quote:
Originally posted by TrueCreation:
"Seriously, early developement of foetus' are anatomically identical, theres no testes, ovaries, penis, or vagina. There are however nipples. These "features" (only a man could call them features) remain as sexual developement continues, with sexual organs then becoming evident. Females haxe two X chromosomes (XX) whilst males are XY. The Y chromosome doesn't do much other than push the development of structures in other directions. If you like, the nipples are female, & are on the Y chromosome, WHICH MALES ALSO POSSESS, but the true sex XX XY differences are not expressed until after the nipples are formed."
--Thanx, I was going to include something on this, but my first question was going to be where is the information condensed(is it located in XY chromosomes) before the human fetus grows or something along that line.
Good question, the very thought occurred to me. My information differs from AiGs, there is no sexual anatomical difference between males & females for 10-15 weeks after conception.
http://www.sciencenet.org.uk/database/Biology/Original/b00013d.html"Both boys and girls appear to be anatomically identical for the first 10-15 weeks after conception. By that time the tissue that eventually forms the nipples is already formed. Later, boys and girls start to develop differently and continue to develop their sexual characteristics after birth. They both retain nipples but only females develop breasts at puberty. "
I'm guessing now, I would say the information to form nipples is somewhere on the other 22 chromosome pairs, but the "start" gene to turn those nipples into something that can express milk is on the X chromosome. If there is no expression of the X-Y chromosomes before 10-15 weeks, that is.
This begs a larger question, & as I'm in need of reading material soon, this could be the subject. How much information is actually on the X & Y chromosomes? Is it just the sex "Hox" genes that direct sexual developement, or the genes that are causal to sex characteristics as well? Perhaps (& probably) a mixture.
Mark
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Occam's razor is not for shaving with.