In minks, the gene for brown fur dominates the gene for platinum coloration. Determine the genotypes

In minks, the gene for brown fur dominates the gene for platinum coloration. Determine the genotypes of the parental forms if out of 146 minks born in the everrosovkhoz, 117 are brown and 29 are platinum.

Let the gene that determines the development of brown fur in minks be designated as C, then the gene for platinum fur will be c.

Minks with platinum-colored fur will be homozygous – cc, because this is a prerequisite for the phenotypic realization of this trait. Parents of such cubs must carry platinum fur genes (c) in their genotypes, that is, at least be heterozygous.

In the offspring, a phenotypic splitting of the 3: 1 type was obtained, this speaks in favor of the maximum number of dominant genes transmitted to the offspring, which allows us to consider the version of the heterozygosity of both parental individuals as a priority.

Let minks – parents be heterozygous, let’s write down their Cc. They have brown fur and produce C and C germ cells.

The offspring of such minks will look like this:

brown homozygote pups (CC) – 25%;

brown cubs – heterozygotes (Cc) – 50%;

cubs are homozygotes with platinum fur (ss) – 25%.

The obtained theoretically splitting confirms the version of the heterozygosity of both parental individuals.

Answer: the parental minks of the fur farm are heterozygotes.