You are studying two linked genes in lizards. You have two females and you know

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? The two genes arc assorting independently in female 1 and arc linked in female 2. The two genes are linked in female 1 and are assorting independently in female 2. The two alleles are in the coupling configuration in female 1 but in the repulsion configuration in female 2. The two alleles are in the repulsion configuration in female 1 but in the coupling configuration in female 2. The two genes are likely located on a sex chromosome in female 1 and are likely located on an in female 2.

Explanation / Answer

A. Female 1 the genes are linked together. The recombination offspring gets very low offspring compare to parental offspring it shows that genes are linked and not independently assort.

Female 2 recombination offspring gets very high compare to parental offspring but also its is linked because if 2 genes are assort independently it has to show the ratio of 1:1:1:1 in test cross. Both F1 and F2 females are linked.

C. Female 1 The parental offspring is high it shows AB / ab. In this the dominant and recessive alleles remain together. It shows coupling.

Female 2 The recombinant offspring is high it shows Ab / aB. The dominant and recessive alleles remain seperate. It shows repulsion.

D. Statement is false.

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