In humans, aniridia, a type of blindness, is due to a domina…

In humans, aniridia, a type of blindness, is due to a dominant gene A.  Migraine headaches are due to another dominant gene M, which is on a different chromosome.  A man who suffers from both conditions (AaMm) marries a woman who suffers from both (AaMm). What are the chances of an offspring having both aniridia and migraine headaches?

 Assume that an incompletely dominant gene controls the feat…

 Assume that an incompletely dominant gene controls the feather color in chickens so that BB produces black, BW produces a slate-gray color called blue, and WW produces asplashed-white.  A second gene on a separate chromosome controls comb shape, with the dominant gene R producing a rose comb and the recessive genes rr producing a single comb. If a pure breeding black, rose-comb chicken is mated with a white, single-comb chicken, what proportion of the offspring will be white, single-comb chickens?