Maternal Inheritance and Maternal Effects

Genetics of Maternal Effects (cont.)

Test the Hypothesis

1. Give the genotypes of the crosses

Generation	Cross 1	Cross 2
Parents	(female) s+s+  x  ss (male)	(female) ss  x  s+s+ (male)
F1	s+s	s+s
F2	3 s+_ : 1 ss	3 s+_ : 1 ss

2. Predict the phenotypes from the genotypes based on the hypothesis

Parental Female Genotypes  (Cross 1)	Parental Female Genotypes (Cross 2)	F1 Female Genotypes	F2 Female Genotypes
s+s+ (right) then F1 is right	ss (left) then F1 is left	all s+s (right) then all F2 right	All 3s+_:1 ss then all F3 3 right:1 left

Conclusions

1. snail coil shape is controlled a nuclear gene
2. the expression of the genotype is delayed by one generation
3. the genotype of the female parent dictates the progeny phenotype