Question

Allozyme phenotypes of alcohol dehydrogenase in the flowering plant Phox drummondii are determined by three co-dominant alleles of a single gene. In one sample of 70 plants the following data were obtained:

Genotype A1A1 A2A2 A3A3 A1A2 A1A3 A2A3
Number 4 24 10 10 2 20
What is the frequency of the A2 allele in this sample?

0.628

0.238

0.557

0.432

0.337

Answer 1

Answer: 0.557

Step-by-step explanation:

First calculate for the genetic frequencies

A1A1 = 4/70 = 0.057

A2A2 = 24/70 = 0.34

A3A3 = 10/70 = 0.14

A1A2 = 10/70 = 0.14

A1A3 = 2/70 = 0.029

A2A3 = 20/70 = 0.29

Frequency of A2 allele therefore = 0.34 + (0.5×0.14) + (0.5×0.29)

= 0.556

The difference in the answer is due to approximations.