posted by zack on .
ok i really need help. like really bad. cant figure it out. ok here it is.
a color blind man marries a woman with normal vision. of their three daughters, one is color blind. one of their two sons is also colorblind. what are the genotypes of the parents?
please help me its confusing!
color blindness is x-linked recessive. The father is obviously xy, where x means the bad gene for color blindness. Now, what is the mother? Since one of the daughters is color blind, the mother must also have bad gene. She is heterozygous...one good and one bad...Xx. If the mother had both good genes, none of the kids would be color blind, and if the mother had both bad genes, ALL the kids would be color blind. Do you see this?
ya i see it now. kinda... lol. thanks.
wait couldn't the mom and the dad both be xy? casue 2/5ths of there kids are color blind
nope. y is the male gene. Mom can't be xy...then she'd be a he!!