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Originally Posted by The_Radiation_Specialist
I have heard some genes are only given to you by your mother and others exclusively by your father. Is this true?
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All of your genes come only from your mother or your father. I suspect what you meant was whether there are some genes that all humans get from their fathers or that all humans get from their mothers, so they're only passed down through the generations along the male "line" or the female "line".
Genes on the Y chromosome are only inherited from the father. Genes on a boy's X chromosome are inherited only from his mother. Genes on the X chromosomes in a girl work like the other 22 chromosome pairs: one chromosome from each parent... with the twist that unlike the other 22 chromosome pairs, her father's X chromosome certainly came from his mother, not from his father or a recombined mix, so the girl essentially gets one of those from her mother and one from her father's mother.
Quote:
Originally Posted by The_Radiation_Specialist
Which genes are actually contained in the X and Y chromosomes and does that mean certain genes are more like to be inherited from a particular parent? i.e sons more likely to get the height gene from mothers, daughters from fathers
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In animals that use a system like ours to determine sex, with one type of chromosome only present in one sex (like the Y in male mammals and the W in female birds) and the other type present in both sexes (like the X in mammals and the Z in birds), the one that's only present in one sex (Y/W) tends to evolutionarily start shrinking soon after first acquiring its sex-determining gene(s), by losing genes that aren't related to the jobs of sex determination and sexual function. All that's left on the human Y is the small number of genes that make the body develop as male instead of as female and control the production of sperm cells. Meanwhile, the other sex chromosome, the one that's present in all members of the species (X/Z), retains the genes it had back when the sex chromosomes were a "normal" chromosome pair, before they began getting used for sex determination. This can include genes for any traits, no matter how seemingly unrelated to sex or to each other.