Question

Two strains of Drosophila (Bravo and X-ray) are homozygous for two variant forms of a particular chromosome. Karyotype analysis indicates that neither strain is missing any part of the chromosome. Genetic mapping of the Bravo strain yields the map below (distances in map units). Bravo and X-ray flies are then mated to produce Bravo/X-ray F 1 progeny. Subsequent crosses measured the genetic distances indicated on the right below

Answer 1

The question involves X-linked inheritance in fruit flies, highlighting how eye color is determined by genes on the X chromosome and demonstrating inheritance patterns in males and females.

Step-by-step explanation:

The question is about X-linked inheritance in Drosophila, commonly known as fruit flies, which was crucial to our understanding of genetics.

X-linked inheritance refers to genes located on the X chromosome.

In Drosophila, the gene for eye color is located on the X chromosome, with red eyes (XW) being dominant over white eyes (Xw).

Since males are hemizygous for the X chromosome (XY), they express whichever allele is present on their single X chromosome.

Females, however, are XX and can be homozygous or heterozygous for eye color.

Examples of crosses between red-eyed and white-eyed Drosophila illustrate how recessive X-linked traits are expressed differently in males and females and how these traits can be traced through generations.