The gene Q codes for skin color. A heterozygote has pink skin and a recessive homozygote has yellow skin. When a Qq is crossed with a qq, what are the possible genotypes in the offspring, and what is the frequency of pink skin and yellow skin offspring?

Question

Quizplus · Accepted Answer

A gamete is produced by the process of meiosis. A gamete is haploid, which means it has only one set of chromosomes. In the case of a heterozygous parent cell (Qq), meiosis will yield two types of gametes, one with "Q" as a genotype and the other with "q". When the parent is homozygous, this results in two gametes with the same genotype "q".
We can use a Punnett Square to determine the percentages of the offspring's phenotype (skin color). Each row and column are labeled with each of the gametes from the parents. Then, you write in what each combination of gametes/alleles would produce as a genotype.
 11ec0fb7_2808_cd8c_95f0_610381d2dc44_NR0002_00 Since Q is dominant and for pink skin, 50% of the offspring (with the genotype Qq), will have pink skin and the other 50% will have yellow skin (qq genotype).

The Gene Q Codes for Skin Color