Question

In a parrot species, feather colour is determined by incompletely dominant sex-linked alleles: Red (ZR) and white (ZW). A pink male is bred many times with a red female. They produce the following offspring: Red male: 79 Pink male: 65 Red female: 82 White female: 46

1 What is the expected phenotype ratio of red males : pink males : red females : white females?

2 How often would this cross result in male offspring that are white?

3 What is your Chi-square value ?

4.Is the deviation between observed and expected phenotype frequencies significantly different from each another?

5 .are the genotypes in Hardy Weinberg Equilibrium

Answer 1

1. Expected Phenotype ratio is : Red Male : Pink Male : Red Female  : White Female 0.29 : 0.24    : 0.30 : 0.17

2. 17% of this cross results in male offspring that are white.

3.Chi square Value:

Phenotypes	Observed Phenotypes(O)	Expected Phenotypes(E)	Difference (O-E)	D2	D2/E
Parental (75%)	207	204	3	9	0.044
Incomplete Dominance(25%)	64	68	-4	16	0.235

Total X2 = 0.279

Degree of freedom =(n-1)= 2-1= 1 ,

4. The P-Value is 0.597357. The result is not significant at p < .05.

The deviation between observed and expected phenotype frequencies not significantly different from each another.

5. Hardy Weinberg Equilibriume equation= Red allele frequency is 0.59, Pink is 0.24 and white is 0.17

p+q=1, 0.77+0.41= 1.18 that is p+q not equal to 1.

P2+2pq+q2=1 , 0.59+0.63+0.17=1.39 that is also not equal to 1.

The genotypes are not in Hardy Weinberg Equilibrium.