Question

Choose the correct answer from the alternatives given.

In mice, Y is the dominant allele for yellow fur and y is the recessive allele for grey fur. Since Y is lethal when homozygous, the result of cross Yy x Yy will be __________.

• A. 3 Yellow: 1 Grey
• B. 2 Yellow,: 1 Grey
• C. 1 Yellow: 1 Grey
• D. 1 Yellow :2 Grey

Answer 1

The correct option is B 2 Yellow,: 1 Grey

Given, that Y is dominant for yellow fur and y is recessive for grey fur, the cross between Yy and Yy will produce. ratio of 1 YY : 2Yy : 1 yy. But as Y is lethal in homozygous condition, hence phenotypic ratio would be 2 yellow (Yy) : 1 grey (yy).