Question

You are studying two linked genes in lizards. You have two females and you know that both are the same genotype, heterozygous for both genes (A/a and B/b). You test-cross each female to a male that is fully homozygous recessive for both genes (a/a and b/b) and get the following progeny with the following phenotypes: Female 1, Female 2 AB - 37 AB - 5 ab - 33 ab - 4 Ab - 4 Ab - 35 aB - 6 aB - 36.

How can you explain the drastic difference between these two crosses?

Answer 1

The drastic difference between the two test crosses can be explained by genetic recombination, which occurs during meiosis. In the first test cross, recombination resulted in nonparental genotypes, while in the second test cross, no recombination occurred.

Step-by-step explanation:

The drastic difference between the two test crosses can be explained by the phenomenon of genetic recombination, which occurs during meiosis. In the first test cross (Female 1), nonparental genotypes (Ab and aB) are observed, indicating that recombination has occurred between the linked genes. In the second test cross (Female 2), only parental genotypes (Ab and aB) are observed, indicating that no recombination has occurred.