In humans, the genes for colorblindness and hemophilia are both sex-linked (loca
ID: 64569 • Letter: I
Question
In humans, the genes for colorblindness and hemophilia are both sex-linked (located ONLY on the X chroromosome). The shorthand for the colorblindness trait is as Xc, while the normal vision X chromosome X is shown as X.
a. If a man and a womean with normal vision marry and have a colorblind son, draw the Punnett sqaure that illustrates how this occured.
b. If the woman remarries to a colorblind man, draw another Punnett sqaure showing the types of children that could e expected from this second marriage.
Explanation / Answer
Normal male( X)
Normal male Y
Carrier women heterozygous (Xc)
XXc (heterozygous female offspring)
XcY (color blind male,as only One Xc inherited
Carrier women heterozygous X
XX normal female
XY normal male
for part b, women remarries,
Normal male( Xc)
Normal male Y
Carrier women heterozygous (Xc)
XcXc (color blind female offspring)
XcY (color blind male,as only One Xc inherited
Carrier women heterozygous X
XXc normal female as heterozygous
XY normal male
Normal male( X)
Normal male Y
Carrier women heterozygous (Xc)
XXc (heterozygous female offspring)
XcY (color blind male,as only One Xc inherited
Carrier women heterozygous X
XX normal female
XY normal male