In the case of a squirrel population containing 1,000 squirrels, there are 2 types of coat colors expressed, red and black. It was determined that 292 squirrels were homozygous dominant, 440 squirrels were heterozygous and 268 were homozygous recessive.
The genotypic frequencies are as follows: Let us allow "R" to represent the allele for dominant, red fur. Let us then allow "r" to represent the recessive allele which when presented in a homozygous pair, results in black fur. If 292 squirrels were homozygous dominant, that means that 29.2% of the squirrels were genotypically RR and red coated. If 440 of the squirrels were heterozygous, then 44% of the squirrel population was Rr and red coated. If 268 of the squirrels were homozygous recessive then 26.8% of the squirrel population was rr and black coated. These percentages were simply obtained by dividing the number of squirrels within the same genotype (rr, RR or Rr) by the total number of squirrels. This number is a translation of the actual number of squirrels having the same genotype into a percentage of the overall population of squirrels.
To determine the allelic frequency, we will first look at the formula provided in the beginning of this paper.