Sex? I was not discussing sex. I was discussing why children in a family, regardless of their sex, usually all look different, because each of their mother's eggs are different.
You are wrong writing that we have 22 chromosome pairs plus either an x or y chromosome. We all have 23 pairs. One of each pair coming from the mother and the other from the father. In the case of males, one pair contains sex determining abilities, the xy pair (x=female, y=male). The female's sex determining chromosome is an xx pair. But unlike the male's it can not also determine sex of future generations, since it has no male parts. In the following I may be incorrect. If so, please offer correction(s): When sperm are created, the male's pairs are separated, making female and male producing sperm, each with a single set of 23 chromosomes. Likewise the female's eggs also have a single set of 23 chromosomes. They are created by combining the 23 pairs, resulting in a unique new single set of 23 chromosomes. It is not a copy of one or the other of her pairs. In other words while a man's x-sperm are all alike and his y-sperm are all alike, with a women generally each of her eggs is different. Y-chromosomes are the same generation after generation. X--chromosomes are recombinations, generation after generation. The father determines the child's sex. The mother provides the non sex differences, the unigueness, among her children. Both past down their genes. IMHO, JimS [EMAIL PROTECTED] wrote:
You've got it wrong. Humans have 22 paired chromosomes, plus either an X or Y chromosome, the latter either/or determining the sex of the individual.Ruth Ann J & K Sindberg wrote: <snip>Have you ever wondered why our children (except) twins look so different? It is because when the mother's egg is formed, the egg's chromosome is a unique recombination of the mother's 2 x-chromosones. Otherwise there would be only 4 possible chromosome combinations and we could have pairs of children that were twins, but of different ages. If I have got this wrong, please correct me. JimS
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