Question

Feather coloration in the lesser-spotted bird of paradise has a complete dominance relationship in which green feathers are the dominant phenotype and blue feathers are the recessive phenotype. In one population there are 1,024 individuals with the genotype GG, 512 individuals with the genotype Gg, and 64 individuals with the genotype gg. What is the expected frequency of GG individuals

Answer 1

Total number of birds = 1024+512+64= 1600

A. Frequency of GG birds = 1024/1600 = 0.64

B. Frequency of Gg birds = 512/1600 = 0.32

C. Frequency of gg birds = 64/1600 = 0.04

D. According to Hardy Weinberg equilibrium

G²+2Gg+g² = 1 or G+g = 1

G² = 0.64

G= √0.64 =0.8

g² = 0.04

g= √0.04 = 0.2

A chi square test will help to know if the population is in Hardy Weinberg equilibrium.

Expected Observed Expected Deviation d² d²/E

ratio value (O) value (E) , d= O-E

0.8 1092 960 +132 17424 18.15

0.2 108 240 -132 17424 72.6

Chi square, X² =
`\sum d²/E` = 90.75

Degree of freedom = n- 1= 2 - 1 = 1

P value < 0.00001. So it's significant at C value of 0.05.

Therefore, this population doesn't obey Hardy Weinberg equilibrium.