Problem: Finally one last problem, there is a non-mendelian inheritance known as the maternal effect. The inheritance of shell-coiling direction in the snail Limnaea pergra has been studied extensively and exhibits this maternal effect. A snail produced by a cross between two individuals has a shell with a right-hand twist (dextral coiling). This snail produces only left-hand (sinistral) progeny on selfing. What are the genotypes of the F1 snail and its parents?