Читать книгу Horse Genetics - Ernest Bailey - Страница 67

As noted in the previous chapter, each parent transmits one of its two chromosomes to its offspring. Every horse has two copies of every autosomal gene, one from its sire and one from its dam. If the two copies are identical, then the horse is said to be homozygous. If the two alleles are different, then the horse is said to be heterozygous for that trait. Homozygous and heterozygous are terms that refer to the genotype of the horse. Genotype describes the specific alleles present in the horse and is useful to predict what the parent will pass to offspring. Genotype could be called “the genetic recipe” of the individual for the locus. For Extension, the genotypes E/E and e/e would be homozygous genotypes because both alleles are the same. Horses that possess two different alleles at a locus, for example E and e, (genotype E/e) are heterozygotes. The symbols for each of the two alleles, one from the sire and one from the dam, are separated by a slash (/) by convention.