| MadSci Network: Genetics |
Actually the fact that male pattern baldness is a result of a gene
past on from the mother has been known well before the big push for the
human genome project. Also, male pattern baldness is NOT a dominant
autosomal gene. In fact it is a recessive gene on the X chromosome (sex
chromosome). If you are a male you have one X chromosome and one Y
chromosome. Thus, for males, if you have one X chromosome and the recessive
gene on that X chromosome you will have pattern baldness (or whatever
recessive trait).
Females can have pattern baldness as well but they would need
recessive alleles (alternate form of a gene)on both of their X chromosomes
(again females are XX and males are XY,) this is why baldness in women is
rare. Females at least have that extra X to save them from a recessive
allele on the other chromosome.
If you remember each parent donates one sex chromosome to their
offspring. Thus if you are a male we KNOW the Y chromosome came from your
father (because in humans it is the sperm from the male that determins the
sex of the offspring - males make both X and Y carrying sperm)and the X
came from your mother. The allele for pattern baldness is carried on the X
chromosome that means you would inherit pattern baldness from your mother.
Below is a few links that explain what I said in a variety of ways. I
hope they help.
http://nj.essortment.com/malepatternbal_rcad.htm
http://school.discovery.com/homeworkhelp/worldbook/atozscience/b/043320.htm
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http://pc65.frontier.osrhe.edu/hs/science/bktype.htm
Try the links in the MadSci Library for more information on Genetics.