When creating a Punnett square for a dihybrid cross how many

When creating a Punnett square for a dihybrid cross, how many different options are there for the alleles from one parent?

Solution

A Dihybrid cross is involved with 2 genes. each gene has two alleles in accordance with normal inheritance pattern i.e. excluding multiple alleles. In a dihybrid cross, gametes are formed with the following different combinations from one heterozygous parent AaBb

1. AB

2. Ab

3. aB

4. ab

There are four options for 2 genes for which the parent is heterozygous.

However, if the parent is homozygous as in AABB then only 1 type of gamete is produced - AB type i.e. only 1 option.