A farmer has acquired a stallion of the Oryol breed. How can you determine its purebredness?

To determine the purity of the breed of a purchased stallion, you can use a technique called an analyzing crossing.

Let’s say the phenotypic traits of the Oryol breed are determined by the O genome.

Purebred individuals will have a genotype homozygous for this gene – OO.

Horses carrying undesirable genes from another breed latent will be heterozygous – Oo.

It is necessary to cross the analyzed stallion with a mare that has the characteristics of the breed, the genes of which must be excluded or confirmed in the stallion’s genotype. Let’s designate such genes as o, and the mare’s genotype – oo. Such a mare is capable of producing eggs exclusively with recessive genes – Fr.

If the stallion is purebred – OO, then it will produce the same type of spermatozoa O and all offspring from this crossing will have the phenotype of the Orlov breed, due to the uniform heterozygous Oo genotype.

If the horse turns out to be heterozygous, then in the offspring there will be foals showing both signs of the Oryol breed and signs characteristic of the mother’s breed – mares:

foals with the phenotype of the Orlov breed (Oo);

foals with a mare breed phenotype (oo).