Question

A father is Homozygous dominant, and a mother is homozygous recessive for a given trait (G). One of their children marries a person that is heterozygous for that trait. Explain what the genotypic and phenotypic ratios would be for possible children from the newly married couple. Be specific and explain how you came to your results.

Answer 1

Children of a homozygous dominant and homozygous recessive pair are all heterozygous. When a heterozygous individual mates with another heterozygous partner, their children's genotypic ratio will be 1:2:1 for GG:Gg:gg, while the phenotypic ratio will be 3:1 dominant to recessive.

Step-by-step explanation:

When a homozygous dominant individual (with genotype GG) and a homozygous recessive individual (with genotype gg) have offspring, all their children will be heterozygous (Gg) for the gene in question, displaying the dominant phenotype.

If one of these children, with the genotype Gg, mates with a partner who is also heterozygous (Gg), the genotypic ratio of their potential offspring will be 1 GG (homozygous dominant): 2 Gg (heterozygous): 1 gg (homozygous recessive).

Given that the dominant trait is expressed in both homozygous dominant and heterozygous genotypes, the phenotypic ratio will be 3 with the dominant phenotype: 1 with the recessive phenotype.