In Drosophila,singed Bristles (Sn)and Carnation Eyes (Car)are Both Caused by Recessive,X-Linked

question 11

Multiple Choice

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 interbred.The F₂ males are distributed as follows.What is the value of ?² for a test of the hypothesis that the sn and car genes are unlinked? $$\begin{array} { | l | l | } \hline s n \text { car } ^ { + } & 55 \\\hline s n \text { car } ^ { + } & 45 \\\hline s n ^ { + } \mathrm { car } ^ { + } & 45 \\\hline \mathrm { sn } ^ { + } \mathrm { car } ^ { + } & 55 \\\hline\end{array}$$

• A) 0.5
• B) 1.0
• C) 2.0
• D) 0.4
• E) 20