Punnett square 1

Dr. Foster: ‘Let’s look closely at the Punnett square you chose. The structure is good in that you separated each parent’s alleles according to the Law of Segregation—one allele per gamete. However, the way you combined them for the offspring results isn’t quite right. Remember, Aa should split into A and a when forming gametes, not into ‘AAaa.’

Keep in mind that each box in the Punnett square holds one allele from each parent. Once you pair those correctly—A with A, A with a, or a with a—you’ll get genotypes like AA, Aa, or aa. The combination you currently have suggests more than two alleles per offspring, which isn’t possible.

Let’s revise it by focusing on one allele from each parent per box. That way, you’ll have four possible genotype outcomes, each reflecting only two alleles.’

Go to: