Question

In fruit fly genes for red, eosin and white eye colour are allelic and sex linked. Gene for yellow body is linked with white eye with a cross over value of 1.5%. The probable crossover value between eosin and yellow body allele would be then

• A. 1.5%
• B. 3%
• C. 0.75%
• D. data insufficient

Answer 1

The correct option is A 1.5%

Given red, eosin and white eye color are allelic and sex-linked. Also, the gene for the yellow body is linked with a white eye with a crossover value of 1.5%. When genes are linked, instead of asserting independently, the genes tend to stick together during crossing over in meiosis and thus move to the same gamete. Since yellow body-white eye crossover value is 1.5% and white eye and eosin are sex-linked, probable crossover value between yellow body and eosin should be the same, that is 1.5%.

So the correct answer is '1.5%'.