In a population of flowers growing in a meadow, C1 and C2 are autosomal codominant alleles that control flower color. The alleles are polymorphic in the population, with f(C₁) = 0.80 and f(C₂) = 0.20. Flowers that are C₁C₁ are yellow, orange flowers are C₁C₂, and C₂C₂ flowers are red. A storm blows a new species of hungry insects into the meadow, and they begin to eat yellow and orange flowers but not red flowers. The predation exerts strong natural selection on the flower population, resulting in relative fitness values of C₁C₁ = 0.30, C₁C₂ = 0.60, and C₂C₂ = 1.0. Assuming random mating takes place among survivors, what are the genotype frequencies in the second generation?

Key Concepts

Codominance

Codominance is a genetic scenario where two different alleles at a locus are both expressed in the phenotype of a heterozygote. In this case, the alleles C1 and C2 produce distinct flower colors when present together (C1C2 results in orange flowers), demonstrating that neither allele is dominant over the other. Understanding codominance is crucial for predicting the phenotypic ratios in offspring from these alleles.

Natural Selection

Natural selection is a process where individuals with traits better suited to their environment tend to survive and reproduce more than those with less advantageous traits. In this scenario, the predation of yellow (C1C1) and orange (C1C2) flowers by insects leads to a decrease in their frequencies, while red flowers (C2C2) are unaffected. This differential survival impacts the allele frequencies in the next generation.

Genotype Frequencies

Genotype frequencies refer to the proportion of different genotypes in a population. After natural selection, the remaining genotypes will have altered frequencies based on their relative fitness. To calculate the genotype frequencies in the second generation, one must consider the surviving individuals' genotypes and apply the Hardy-Weinberg principle, assuming random mating occurs among the survivors.