Answer:
Epistasis effect result into these offspring
Step-by-step explanation:
Given
spotted coat (S) is dominant to solid color (s) and black (B) is dominant to brown (b)
Genotype of true-breeding black spotted rabbit BBSS
Genotype of true-breeding brown solid rabbit bbss
Genotype of offspring BbSs
In normal crossing between BbSs and BbSs offspring of F1, should produce offspring in the ratio 9:3:3:1
But it does not happens in this case the simple reason could be presence of Epistasis in which the alleles assort independently but do not express themselves because of the following reasons -
a) Interaction between two or more loci thereby resulting into new phenotypes
b) An allele at one locus masks effects of other allele at one or more loci
c) Allele at one locus modifies the effects of alleles at one or more other loci