Question

A cross was carried out between two individuals heterozygous for two pairs of genes was carried out. Assuming segregation and independent assortment, the number of different genotypes and phenotypes obtained respectively would be

• A. 4 and 9
• B. 6 and 3
• C. 9 and 4
• D. 11 and 4

Answer 1

Answer: (C)

In the given question, both parents are heterozygous for two pairs of genes. This means the cross is a dihybrid cross.
Lets assume a dihybrid cross


The genotypic ratio i s l : 2 : l : 2 : 4 : 2 : l : 2 : 1 The phenotypic ratio is 9 : 3 : 3 : 1
$\therefore$ The number of different genotypes and phenotypes obtained would be 9 and 4, respectively.