Reference no: EM132436033

DIHYBRID CROSS

Question 1: About 70% of Americans perceive a bitter taste from the chemical phenylthiocarbamide (PTC). The ability to taste this chemical results from a dominant allele (T) and not being able to taste PTC is the result of having two recessive alleles (t). Having a normal amount of pigments in the skin is dominant (A) and albinism is a lack of pigment in the skin and is recessive (a). A woman who is heterozygous for both traits marries a man who is also heterozygous for both traits. What is the possible phenotypic ratio of their children?

Parents Genotype_____________X______________

Taster/normal skin:

Taster/albino:

Non taster/normal skin:

Non taster/albino:

Phenotypic Ratio= _______:_______:______:_______

Question 2: In the breeding season, male Anole lizards court females by bobbing their heads up and down while displaying a colorful throat patch. Assume for this question that both males and females bob their heads and have throat patches. Now, suppose that lizards who bob their heads fast (F) and have red throat patches (R) are dominant to their counterparts, slow bobbing and yellow throats. A male lizard heterozygous for head bobbing and homozygous dominant for the red throat patch mates with a female that is also heterozygous for head bobbing but is homozygous recessive for yellow throat patches. What is the phenotypic ratio for the offspring of these lizards?