Answer:
0.2 (or 20%)
Explanation:
The allele frequency can be calculated by counting how many times an allele appears in a population and then by dividing this number by the total number of alleles of the gene. In this case,
- Genotype BB = 30 moths >> 60 copies of the B allele
- Genotype Bb= 12 grey moths >> 12 copies of the B allele and 12 copies of the b allele
- Genotype bb= 3 white moths >> 6 copies of the b allele
The total number of copies of the gene is:
Dominant (B) allele = 60 (BB genotype) + 12 (Bb genotype) = 72 B alleles
Recessive (b) allele = 12 (Bb genotype) + 6 (bb genotype) = 18 B alleles
Then, 72 + 18 = 90 alleles
Allele frequencies:
Dominant (B) allele = 72/90 = 0.8 (or 80 %)
Recessive (b) allele = 18/90 = 0.2 (or 20%)