Question

One of the following shows complete linkage.

• A. Male Culex
• B. Male Drosophila
• C. Female Drosophila
• D. Neurospora

Answer 1

The correct option is B Male Drosophila

In male Drosophila, complete linkage was observed. If linkage is complete, there should be parental combinations only and no recombination. Morgan reported a complete linkage in Drosophila. When ordinary male wild fly with grey body and normal wings were crossed with female having black body and vestigial wings, in F${}_1$, hybrids were all grey bodied and normal winged (with dominant characters). But when F${}_1$, male is back crossed with recessive female parent only two types of individuals in F${}_2$ generation were produced instead of expected four. These two types were grey bodied and normal winged and black bodied and vestigial winged in equal number, thus indicating the complete linkage.