In Drosophila, sepia eyes (se), curled wings (cu) and ebony body (e) are found,
ID: 49040 • Letter: I
Question
In Drosophila, sepia eyes (se), curled wings (cu) and ebony body (e) are found, in this order, on chromosome 3. Sepia is 22 map units from curled, whiich is 12 map units from ebony. A true-breeding female with sepia eyes and ebony body is crossed to a true-breeding male who has curled wings. The resulting F1 progeny from this cross are all wild type. An F1 female is test crossed to a male expressing all three traits. Assuming a coefficient of coincidence of 1:
a)what proportion of the f2 progeny will express only the sepia trait?
b)If there are 1000 total flies, what number will express curved only?
Explanation / Answer
Since, all the above-mentioned genes are present on the same chromosome, so obviously they are physically linked.
also, since the coefficient of coincidence of 1 mentioned then obviously there should not be any interference between expected double cross over frequ. and observed double cross over frequ.
a) probably, the proportion of the F2 progeny expressing sepia trait would be 22/100 x1000 = 220.
b) The curved feature has not mentioned in the Q. just notice that...