C57BL/6 mice have low pathology of worm infection whereas CBA mice - high pathology. The pathology is associated with granuloma size in liver. The phenotype is dominantly inherited for B6 in that F1 mice have low pathology. By crossing F1s to CBA, Patrick generated 49 backcross mice with 17 mice having low pathology and the rest being high. Of those 17 N2s, 2 mice were homozygous for D17Mit62 and 5 mice were homozygous for D4Mit80. Out of high pathology N2s, 4 were heterozygous for D17Mit62 and 9 were heterozygous for D4Mit80.
Is there any linkage of the phenotype with each of the two markers? If yes, which one is stronger? Is it significant? (8 points)
7. If a black female mouse is crossed to a white mouse to produce two offspring in each of three litters, all of which are black, what is her probable genotype? (3 points)