Reference no: EM132680698

In Drosophila, the genes for eye color and type of wing vein are very closely linked. The normal wild type alleles, R and N, are both dominant and result in red eyes and thin wing veins, respectively. The recessive alleles, r and n, code for brown eyes and thick wing veins, respectively. Flies homozygous for r and N are crossed to flies homozygous for R and n to obtain doubly heterozygous F progeny. If you use these F flies to conduct a test cross to a rrnn individual, what phenotypic ratio would you observe in the offspring, assuming that the genes are too closely linked for crossing over to have occurred between them?

(choose one)

1 brown, thin: 1 red, thick

1 brown, thick: 1 red, thin

1 brown, thin: 2 red, thin: 1 red, thick

1 brown, thick: 2 red, thin: 1 red, thin