We have looked at how to derive the haploid gametes in a monohybrid cross - we are now going to look at how to derive the gametes for a dihybrid cross.

In a dihybrid cross you have two alleles that you wish to follow, let's call them 'A' and 'B'. So, this means that 'A' would be dominant, and 'a' would be recessive; and 'B' would be dominant and 'b' would be recessive. The different genotypes would be represented as AABB, AaBB etc.

The Punnett Square Calculator cannot automatically work out the gametes for you, but it can perform the crosses, hence you need to know what gametes to put in, AND you must understand how the calculation works as you won't have the calculator available in exams (plus you should NEVER trust a computer to do a calculation that you don't understand).

You wish to perform a dihybrid cross with an organism that has 2 legs, and 2 eyes. You know that one allele is dominant and produces an animal with 4 legs, and the other is recessive and produces an animal with 4 eyes.