1. A man with red-green color blindness marries a woman with normal vision. Their first child, a boy, is color-blind.

a) Diagram the cross above.

b)The couple have a second child, a girl, with normal vision. This girl grows up and becomes pregnant with a child she knows to be a boy. The father of this child has normal vision. What is the probability that this child will have red-green color blindness? Diagram the cross.

Question

1. A man with red-green color blindness marries a woman with normal vision.  Their first child, a boy, is color-blind. 

a) Diagram the cross above.

b)The couple have a second child, a girl, with normal vision.  This girl grows up and becomes pregnant with a child she knows to be a boy.  The father of this child has normal vision.  What is the probability that this child will have red-green color blindness?  Diagram the cross.

anonymous · Answer

The main thing with this question is that the color-blindness alleles are X- linked ie the genes that give the color - perceiving ability to unaffected individuals are on the X - chromosome. Normally the woman has two normal copies of the gene in question which means that all offspring have normal vision but this isn't the case in the question. Hope these hints help - let me know if I can be of more assistance.

anonymous · Answer

http://waynesword.palomar.edu/colorbl1.htm