In a hypothetical population of 1000 frogs there exists a gene with two alleles. 280 of the frogs are homozygous dominant (DD), and 220 are homozygous recessive (dd). What is the frequency of heterozygotes in the population?
A)0)0
B)0)28
C)0)22
D)0)50

Question

Quizplus · Accepted Answer

To find the frequency of heterozygotes, first, calculate the total number of alleles in the population (2 alleles per frog * 1000 frogs = 2000 alleles). Given 280 DD frogs (560 D alleles) and 220 dd frogs (440 d alleles), we can find the frequency of the D allele (p) and the d allele (q) in the population. p = 560/2000 = 0.28, q = 440/2000 = 0.22. The frequency of heterozygotes (2pq) = 2 * 0.28 * 0.22 = 0.1232 or 12.32%. However, since the question asks for the percentage of the population that is heterozygous, not the allele frequency, we need to calculate it differently. We know 500 frogs are either DD or dd, leaving 500 frogs unaccounted for, which must be heterozygous (Dd). Therefore, 500 out of 1000 frogs are heterozygous, making the frequency 50%.

In a Hypothetical Population of 1000 Frogs There Exists a Gene