Question

You sample a population of Poecillia reticulata, fish commonly known as guppies, and obtain following genotype counts. Is the population in Hardy Weinberg Equilibrium? If not, how many generations until would it take to get there (assuming this population is not violating any of the assumptions of Hardy Wienberg)? Show your calculations. Genotype AA Aa aa # sampled 219 45 6 Note: this question is about chi-squared test. Not just P+Q.

Answer 1

Individuals with genotype AA= 219

Individuals with genotype Aa= 45

Individuals with genotype aa= 6

Total = 270

Observed and expected frequency:

	Obs	Exp
AA	81.11111	25
Aa	16.66667	50
aa	2.222222	25

Chi-square Analysis

(O-E)2	E2	(O-E)2/E2
3148.457	625	5.037531
1111.111	2500	0.444444
518.8272	625	0.830123
	Total	6.312099

P value<0.05

The null hypothesis is rejected and thus alternative hypothesis that there is a difference between the observed frequency and the expected frequency of Hardy-Weinberg's law.