A Behavioral Biologist Suspects the "N" Locus to Be Involved

Multiple Choice

A behavioral biologist suspects the "N" locus to be involved in the learning ability of dogs.Learning is measured through a standardized test in which each dog can score from 0 (very poor) to 20 points (excellent) .In an experiment,the mean score was 15.6 for dogs of genotype N/N,12.1 for dogs of genotype N/n and 7.2 for those of genotype n/n.What is the dominance/additivity ratio for this locus?

A) 0
B) higher than 0,but lower than 0.5
C) 0.5
D) higher than 0.5,but lower than 1
E) 1