Question

A maternal effect can cause the offspring phenotype ratio to depart from that of classic mendelian inheritance. in a species of snail, the dominant allele n codes for right-handed shell coiling and recessive allele n codes for left-handed shell coiling. if an nn female with right-handed shell coiling mates with an nn male, what is the shell coiling phenotypic ratio of their offspring?

Answer 1

If both parents are "nn" and this means they have for the same gene two alleles that are equal, and the mother has right-handed shell coiling which is dominant and the father is equally nn, then, the phenotype ratio, accordingly with the classic mendelian inheritance (there's no other information as for the variation expected) will be all of the offspring nn.