Heredity, Natural Selection, and Evolution

Early Studies in Heredity

What is meant by the terms “true breeding,” homozygous, and heterozygous?

Individuals when bred to others of the same genotype produce only offspring of that genotype; this is called true breeding. When two inherited alleles are alike, they are said to be homozygous individuals (AA, aa), an example of true breeding; if the two members of the allelic pair are different, the combination is said to be heterozygous individuals (Aa; also called hybrid).


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