In the offspring from crossing the gray fruit fly with the black one, 290 black and 269 gray fruit flies were obtained.

In the offspring from crossing the gray fruit fly with the black one, 290 black and 269 gray fruit flies were obtained. What are the genotypes of parents and offspring? The sign of black body color is recessive. Gray dominant

Let us designate the gene that causes the black coloration of the fruit flies as c, and the gene that causes the gray coloration of their bodies as C.

Black Drosophila is homozygous for the gene for black body coloration, because only in this way the recessive trait can be phenotypically realized.

Splitting based on body color in the offspring is an approximate ratio of 1: 1, which is typical for crossing a heterozygote with a homozygote for a recessive trait.

A heterozygous gray Drosophila will be recorded as Cc. It will produce two types of germ cells – c and C.

Drosophila homozygous for the recessive gene will have a black body coloration and a cc genotype. Such a fly produces the same type of germ cells – p.

Offspring includes the following options:

fruit flies with a black body (cc) – 50%;

Drosophila with a gray body (Cc) – 50%.

The resulting percentage corresponds to the actual one presented in the problem statement.

Answer: parents are homozygous for the gene for black color (cc) + heterozygote (Cc); children: 50% are gray heterozygotes (Cc), 50% are black homozygotes (cc).