In humans the presence of chin and cheek dimples is dominant to the absence of dimples, and the ability to taste the compound PTC is dominant to the inability to taste the compound. Both traits are autosomal, and they are unlinked. The frequencies of alleles for dimples are D = 0.62 and d = 0.38. For tasting, the allele frequencies are T = 0.76 and t = 0.24. Determine the frequency of genotypes for each gene and the frequency of each phenotype.

Key Concepts

Mendelian Genetics

Mendelian genetics is the study of how traits are inherited through generations based on the principles established by Gregor Mendel. It involves understanding dominant and recessive alleles, where dominant traits mask the expression of recessive ones. In this context, the presence of dimples and the ability to taste PTC are dominant traits, which means individuals with at least one dominant allele will express these traits.

Hardy-Weinberg Principle

The Hardy-Weinberg principle provides a mathematical framework for understanding allele and genotype frequencies in a population at equilibrium. It states that allele frequencies will remain constant from generation to generation in the absence of evolutionary influences. This principle is essential for calculating expected genotype frequencies based on given allele frequencies, allowing for predictions about the distribution of traits in a population.

Phenotype and Genotype Frequencies

Phenotype frequencies refer to the observable traits expressed by individuals in a population, while genotype frequencies refer to the genetic makeup underlying those traits. For the traits in question, the frequencies of genotypes can be calculated using the allele frequencies and the Hardy-Weinberg equations. Understanding how to derive these frequencies is crucial for determining the distribution of dimples and tasting ability in the population.