Industrial melanism refers to the dark pigmentation that evolved in some insects
ID: 161648 • Letter: I
Question
Industrial melanism refers to the dark pigmentation that evolved in some insects, giving them protective coloration on vegetation darkened by soot in heavily industrialized areas prior to the requirement for smokestack filtration. In one heavily polluted area near Birmingham, England in 1956, 87% of moths of the species Biston betularia had black bodies due to the presence of a dominant gene for melanism (Kettlewell 1956). Estimate the frequency of the dominant allele in this population and the frequency of melanics that are heterozygous assuming HWE conditions.
Explanation / Answer
Acc to hardy weinberg law:
p2 + 2pq + q2 = 1 and p + q = 1
p = frequency of the dominant allele in the population
q = frequency of the recessive allele in the population
p2 = percentage of homozygous dominant individuals
q2 = percentage of homozygous recessive individuals
2pq = percentage of heterozygous individuals
where p=.87,as p+q=1 then q=.13
p=.87,frequency of dominant allele
2pq=2*.87*.13=.2262 which is frequency for hetrozygous