Self Assessment Answer # 5
for Lesson 12

by Dr Jamie Love Creative Commons Licence 2002 - 2005


"If its got a Y it's a guy!" so this child will be male.

He will have one Barr body because "XXY" minus one "X" equals one "X" that becomes the Barr Body.

During meiosis his sex chromosomes will segregate as
XXY -> XX and Y
or
XXY -> X and XY
So he can make four different kinds of sperm, with respect to sex chromosomes = XX, Y, X and XY.

Simply fuse those four types of sperm with a (normal X carrying) egg to give
XX = X -> XXX (Trisomy X syndrome)
Y + X -> XY (a normal guy)
X + X -> (a normal gal)
XY + X -> XXT (Klienfelter syndrome, like himself)
(You weren't asked to name the phenotypes but I thought I'd remind you.)


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