Sickle cell anemia is caused by a recessive allele. Roughly 1 out of every 500 african americans is afflicted with sickle cell anemia. How would you use the hardy weinberg equation to calculate the % of heterozygotes for sickle cell allele (.002=q^2)?

1 Answer

The percent of heterozygous individuals in African American population, for sickle cell allele, is roughly 8.54%.

Explanation:

The Hardy-Weinberg equation is:

p2+2pq+q2=1 and also p+q=1

  • where p2 is the percentage of homozygous dominant phenotype
  • where 2pq is the percentage of heterozygous dominant phenotype
  • where q2 is the percentage of homozygous recessive phenotype

One double recessive afflicted individual means there are two individuals among 1000. Thus,

q2=0.002

q=0.0447

Then

p+q=1

p=1q

p=0.9553

p2=0.9126

2pq=2(0.9553)(0.0447)=0.0854

Thus % of heterozygous individuals in the population is =8.54%

Double Check:

0.9126+0.0854+0.002=1