Question

With respect to Morgan's dicovery of sex linkage in Drosophila, select the incorrect statement.

• A. $F_1$ flies were all red
• B. ${F_2}^{}$ included both red and white
• C. All white-eyed flies in ${F_2}^{}$were females
• D. The recessive allele in question was expressed only in males

Answer 1

The correct option is C All white-eyed flies in ${F_2}^{}$were females

In 1910, T. H. Morgan demonstrated sex linkage phenomenon in white mutant Drosophila. A gene had undergone a change that resulted in a phenotypic alteration. This change expressed itself as white eyes rather than the normal red eyes. The white-eyed male first discovered was mated with a red-eyed female. The $F_1$flies were all red-eyed but the ${F_2}^{}$ included both red and white in 3:1 ratio. All white-eyes flies in the ${F_2}^{}$ generation, however, were males. About half of the ${F_2}^{}$ maled had white eyes and half had red eyes, but all females had red eyes. The recessive allele was expressed only in males.