In Drosophila , singed bristles (sn) and carnation eyes (car) are both caused by
ID: 80666 • Letter: I
Question
In Drosophila, singed bristles (sn) and carnation eyes (car) are both caused by recessive, X-linked alleles. The wild-type alleles (sn+ and car+) are responsible for straight bristles and red eyes, respectively. A sn car female is mated to a sn+ car+ male and the F1 progeny are testcrossed. What is the value of X2 for a test of the hypothesis that the sn and car genes are unlinked? The F2 are distributed as follows
sn car
55
sn car+
45
sn+ car
45
sn+ car+
55
200
sn car
55
sn car+
45
sn+ car
45
sn+ car+
55
200
Explanation / Answer
The value of x2 is 2.00. As revombination does not occur in male and the total is 200 progenies.