Question

Which of the following genetic crosses would be predicted to give a phenotypic ratio of 9:3:3:1?

a. SSYY x ssyy

b. SSyy x ssYY

c. SsYy x SsYy

d. SsYY x SSYy

Answer 1

Which of the following genetic crosses would be predicted to give a phenotypic ratio of 9:3:3:1?
ANSWER - c. SsYy × SsYy
Explanation - options a, b & d Doesn't give the phenotypic ratio 9:3:3:1 after there crosses, Because option c having both the heterozygous allele contains by male and female parents so it produces 4 types of gamete SY,Sy,sY,sy when it crosses with SY,Sy,sY,sy this gamete produces total 16 progeny which is not possible by options a,b & d because it doesn't contain both heterozygous allele in either female parent or male parent.