Assume 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 testcross 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:

AB-37

ab-33

Ab-4

aB-6

Female 2:

AB-5

ab-4

Ab-35

aB-36

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