Question

1. How do you get the expected from the observed in order to perform a chi square with the following data?

Original cross was between a mutant male that had white eyes and vestigial wings and a female that had red eyes and normal wings.

F1 Progeny Class Data Results
Phenotype (Eye, Wing)	Wild Type eye, Wild Type wings	Wild Type eye, Vestigial wings	White eye, Wild Type wings	White eye, Vestigial wings
Male	242	2	1	8
Female	250	2	0	9
Total	492	4	1	17
Total Progeny: 514

Answer 1

In this case, the maximum no. of progeny are from red eyes and normal wings so we assume they are the dominant genes.

Let us denote red eyes by RR, white eyes by rr, normal wings by NN and vestigial wings by nn.

The Cross is as follows: RRNN(female) x rrnn(male)

	RN	RN
rn	RrNn	RrNn
rn	RrNn	RrNn

Expected frequency according to this cross should be 1:0 = Wild type eyes and Wild Type wings: others

The expected no. of progeny for:

Wild Type eye, Wild Type wings = 1x514 = 514

Wild Type eye,Vestigial wings = 0

White eye, Wild Type wings = 0

White eye, Vestigial wings = 0

These can now be used to find the chi-squared function.