1. A dominant gene (A) causes yellow color in rats, the dominant allele on another independent gene (R) produces black coat color. When the two dominants occur together (A_ R_) they interact to produce gray coat color. Rats of the genotype aa are cream-colored. If a gray male and a yellow female, when mated, produce offspring approximately 3/8 of which are yellow, 3/8 gray and 1/8 cream, and 1/8 black, what are the genotypes of the parents

Parents: Yellow (Aarr) and Grey (AaRr)

Explanation:

Given:

allele A = yellow

allele R = black,

Heteroozygous = gray

Genotypes of the parents:

yellow (Aarr) - female

gray (AaRr) - gray

cross between these

Parents: Yellow (Aarr)  and Grey (AaRr)

Gametes: (Ar, ar) and (AR, Ar, aR, ar)

F1 (Punnet square)

| AR | Ar | aR | ar

Ar | AARr (gray) | AArr (yellow) | AaRr (gray) | Aarr (yellow)

ar | AaRr (gray) | Aarr (yellow) | aaRr (black) | aarr (cream)

Ratio: 3/8 yellow : 3/8 gray : 1/8 cream : 1/8 black

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.