A genetics question I still don't understand

AllenMontg allenmontg at aol.com
Mon Dec 30 20:09:53 EST 1996


A man dies, he's got a daughter and a nephew, the son of his brother.
Because of the inheritance an alleged son drops by, claiming to be the
son of the
man by a misstress.
Whom should they check besides the alleged son.
a) the mistress
b) the nephew
c) the daughter

I thought the nephew because of the y-chromosome wich have to be
identical.
>A friend of mine pointed out that if the real father wasn't the man who
>died but some far family member by male line with the same father or
grandfather
>or greatgrandfather et cetera they also would have the same y-chromosome
>Therefor he chose the daughter. The quiz said that it would be the nephew
but I >see no faults in the remark of my friend Hans.
>Hope I'll hear from you,

Your friend is right.  Even given the Y chromosome, we're only talking
about one chromosome, out of a total of 46.  On the other hand, two people
with the same father, but different mothers, could be expected to share
12.5% of their chromosomes in common.  If they had the same mother and
father, that figure would rise to 25%.

http://members.aol.com/AllenMontg/drugspy.html

Allen D. Montgomery




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