Question

In Drosophila, white eye colour is a recessive X-linked trait while red eye colour is dominant. A white eyed female is crossed with a red eyed male. The female offspring with red eye colour would be.
A) 100%
B) 50%
C) 25%
D) Zero

Answer 1

Hint:X-linked recessive inheritance has genetic disorders related to mutations of the genes present on the X chromosome. A male having these mutations will be affected as he carries only one X chromosome. While a female with a mutation in one of the genes, with a normal gene on the other X chromosome, remains unaffected.

Complete answer:
1) The eye colour quality is connected with sex and is show on the X-chromosome. X-chromosome doesn't pass specifically from father to the offsprings of the same sex but takes after a criss-cross legacy, which is exchanged from one sex to the sibling of the inverse sex.
2) The white eye colour characteristic is passive and sex-linked, it has its impact on guys since of one X-chromosome. The female flies are able to appear white-eye characteristic in case both X-chromosomes have latent alleles for the white eye.
3) Morgan concluded that the X chromosome incorporates a quality.

After crossing between white-eyed female (XW/XW) with a red-eyed male (X+Y), within the F1 era, all the female flies were red-eyed and all the male flies were white-eyed. This result isn't the same as anticipated from the typical Mendelian proportion. This appears that the inheritance pattern of eye colour is subordinate on X-chromosome. Subsequently, it was concluded that the quality of eye colour is found on the X-chromosome.

Hence, the correct answer is option option ‘A’ i.e, '100%'

Note:Haemophilia is known to be a sex-linked disorder which is present in X-chromosome. The males have only one X-chromosome and are thus affected while the females are the carriers.