Describe on this example the cytological basis of monohybrid crosses.

P is the parent generation, F1 is the first generation of descendants, F2 is the second generation of descendants, A is the gene responsible for the dominant trait, and the gene responsible for the recessive trait.
As a result of meiosis, the gametes of the parental individuals will contain one gene responsible for the inheritance of a certain trait (A or a). In the first generation, somatic cells will be heterozygous (Aa), so half of the first generation of gametes will contain gene A, and the other half will contain a. As a result of random combinations of gametes in the second generation, the following combinations will arise: AA, Aa, aA, aa. Individuals with the first three combinations of genes will have the same phenotype (due to the presence of a dominant gene), and with the fourth – another (recessive).

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