In horses, the genes that determine the color of the suit (A – black, a – chestnut) and leg length

In horses, the genes that determine the color of the suit (A – black, a – chestnut) and leg length (B – long legs, b – short legs) are located in different pairs of chromosomes. Breeders crossed individuals with different leg lengths from the first generation. Determine the genotypes of the parents, the genotypes and phenotypes of the offspring obtained as a result of crossing a black long-legged horse, heterozygous for the second trait, and a bay short-legged mare. Make a scheme for solving the problem. What offspring can be expected from interbreeding F1 offspring with each other? By what law is this trait inherited? Note: the interaction of genes during inheritance of traits in horses is not taken into account in the problem.

Black long-legged horse, heterozygous for the second trait – AABb, according to the designations introduced in the problem statement. Such a horse produces two types of spermatozoa – Ab and AB.

A bay short-legged mare is aabb, because for the phenotypic realization of these traits classified as recessive, the horse’s genotype must be homozygous for the genes of these traits. This mare produces eggs of one type – ab.

From crossing the described horse and mare, we get offspring, represented by the following options:

black foals with short legs (Aabb) – 50%;

black foals with long legs (AaBb) – 50%.

The law by which the color and leg length of horses are inherited in this problem is called the law of independent inheritance.