In the Snail Limnaea Peregra, Shell Coiling Is Determined by the Nuclear

Multiple Choice

In the snail Limnaea peregra, shell coiling is determined by the nuclear alleles S (dextral) and s (sinistral) . This gene is a maternal effect gene that influences egg formation, which in turn influences whether the snail that hatches from the egg has a shell that coils to the right (dextral) or left (sinistral) . A female sinistral snail is mated with a sinistral male snail. The genotypes of both are unknown. All the F1 progeny are dextral. When the members of the F1 generation are crossed, they yield an F2 generation that is ³/₄ dextral and ¹/₄ sinistral.
-What was the genotype of the mother of the female snail?

A) SS
B) Ss
C) ss
D) Ss or ss
E) SS or Ss