The direction of shell coiling in the snail Lymnaea peregra (discussed in the introduction to this chapter) results from genetic maternal effect. An autosomal allele for a right-handed, or dextral, shell (s+) is dominant over the allele for a left-handed, or sinistral, shell (s). A pet snail called Martha is sinistral and reproduces only as a female (the snails are hermaphroditic). Indicate which of the following statements are true and which are false. Explain your reasoning in each case. a. Martha’s genotype must be ss. b. Martha’s genotype cannot be s+ s+. c. All the offspring produced by Martha must be sinistral. d. At least some of the offspring produced by Martha must be sinistral. e. Martha’s mother must have been sinistral. f. All of Martha’s brothers must be sinistral
The direction of shell coiling in the snail Lymnaea peregra (discussed in
the introduction to this chapter) results from genetic maternal effect. An
autosomal allele for a right-handed, or dextral, shell (s+) is dominant
over the allele for a left-handed, or sinistral, shell (s). A pet snail called
Martha is sinistral and reproduces only as a female (the snails are
hermaphroditic). Indicate which of the following statements are true and
which are false. Explain your reasoning in each case.
a. Martha’s genotype must be ss.
b. Martha’s genotype cannot be s+ s+.
c. All the offspring produced by Martha must be sinistral.
d. At least some of the offspring produced by Martha must be sinistral.
e. Martha’s mother must have been sinistral.
f. All of Martha’s brothers must be sinistral
Trending now
This is a popular solution!
Step by step
Solved in 2 steps