Determine the parental genotypes if 25% of the hybrid offspring of guinea pigs has smooth hair and 75% is wavy.

The law of splitting (the second law of Mendel).
Mendel grew plants from the hybrid pea seeds (Aa), which he self-pollinated, and sowed the resulting seeds again. The result was a second generation of hybrids, or F2 hybrids. Among the latter, splitting was found for each pair of alternative characters in a ratio of about 3: 1, i.e. 75% of the plants had dominant characters (purple flowers, yellow seeds, smooth seeds, etc.) and one 25% had recessive (white flowers , green seeds, wrinkled seeds, etc.).