In: Biology
In Drosophila the recessive alleles for white eyes is X-linked (normal eye color is red) and the recessive allele for vestigial wings is autosomal. A female heterozygous for both of these traits is crossed with a white-eyed vestigial male. What proportion of the FEMALE progeny will be white-eyed with vestigial wings.?
(a) 100 % (b) 75 % (c) 50 % (d) 25 % (e) 0 %
let the alleles be Xw+ - red eye colour, Xw- white eye colour
v+- wildtype wings, v- vestigial wings
Xw+Xwv+v is the genotype of the female heterozygous for both traits.
and genotype of the male with white eyes and vestigial wings si XwYvv
Xw+Xwv+v * XwYvv
Xw+v+ | Xw+v | Xwv+ | Xwv | |
Xwv | Xw+Xwv+v ( female with red eyes and normal wings) | Xw+Xwvv ( female with red eyes and vestigial wings) | XwXwv+v ( female with white eyes and normal wings) | XwXwvv ( female with white eyes and vestigial wings) |
Yv | Xw+Yv+v( male with red eyes and normal wings) | Xw+Yvv( male with red eyes and vestigial wings) | Xw+Yv+v( male with white eyes and normal wings) | XwYvv( male with white eyes and vestigial wings) |
proportion of the FEMALE progeny will be white-eyed with vestigial wings= number of females with white-eyed with vestigial wings/total number of female progenies=1/4
so the answer in percentage is 1/4100=25%
so the answer is d) 25%