Question

The allele for the ability to roll one's tongue is dominant over the allele for the lack of this ability. in a population of 500 individuals, 25 percent show the recessive phenotype. how many individuals would you expect to be homozygous dominant and heterozygous for this trait

Answer 1

25% ; 50%

Step-by-step explanation:

Assuming the dominant allele for the rolling tongue is P, then the recessive allele will be p.

The population unable to roll their tongue will be recessive dominant pp = 25% = 0.25

To find the frequency of the p allele then = (square root of 0.25) = 0.5

Remember the Hardy Weinberg equation of p + q = 1 & p² +2pq + q² = 1

Therefore P = 1 – 0.5 = 0.5

Homozygous dominant individuals will be P*P = 0.5*0.5 = 0.25 * 100 = 25%

Heterozygous individuals will be 2*P*p= 2*0.5 *0.5 = 0.5 * 100 = 50%