In mice, the dominant yellow gene in the homozygous state is lethal. The gray gene is recessive.

In mice, the dominant yellow gene in the homozygous state is lethal. The gray gene is recessive. What is the offspring when crossing a. yellow mice with gray and b. yellow mice with yellow?

Let’s designate the gene that causes the yellow color of the mice’s fur as C, then the gene for the gray color of their fur will be c.

Viable mice with yellow hair will be heterozygotes – Cc. They will produce C and C germ cells.

Gray mice will be cc, because homozygosity is a condition for the realization of this trait. They will produce the same type of sex cells with.

A. When crossing gray mice with yellow offspring will look as follows: 50% Cc – live mice with yellow hair, 50% Cc – gray mice.

B. When crossing yellow mice with each other, 25% of the offspring will not be viable, since genotypically it will be represented by homozygotes for the dominant gene – CC; 50% of the mice will be yellow (Cc); 25% of the mice will be gray.