have x + + = x x o o o x 3 x o x o x o Combinations o x x x o o + 3(3/4 x 1/4 x + 3(3/4 x 3/4 x = 1/4) 1/4) Note: the probability of the disease (x) = 1/4 & the probability of being normal (o) = 3/4 all three children will have the disease iii. 1/4 x 1/4 x 1/4 = 1/64 at least one child out of three will be phenotypically normal iv. (Note: Remember that the probabilities of all possible outcomes always add up to 1) 1 - 1/64 = 63/64 Problem g In tigers, a recessive allele causes an absence of fur pigmentation (a "white tiger") and a cross-eyed condition. If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross-eyed? What percentage will be white? Using the Punnett square below where P = normal pigmenation and p = white then 25% will be white (pp) and all of the white offspring will also be cross-eyed Problem i
have x + + = x x o o o x 3 Combinations x o x o x o o x x x o o + 3(3/4 x 1/4 x 1/4) + 3(3/4 x 3/4 x 1/4) = Note: the probability of the disease (x) = 1/4 & the probability of being normal (o) = 3/4 iii. all three children will have the disease 1/4 x 1/4 x 1/4 = 1/64 iv. at least one child out of three will be phenotypically normal (Note: Remember that the probabilities of all possible outcomes always add up to 1) 1 - 1/64 = 63/64 Problem g In tigers, a recessive allele causes an absence of fur pigmentation (a "white tiger") and a cross-eyed condition. If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross-eyed? What percentage will be white? Using the Punnett square below where P = normal pigmenation and p = white then 25% will be white (pp) and all of the white offspring will also be cross-eyed Problem i