SAT Subject Biology Practice Question 90: Answer and Explanation
20. Which of the following patterns of inheritance describes interactions between multiple genes?
B. Sex linkage
D. Simple dominance
E. Homozygous recessive
Correct Answer: A
Epistasis is the condition in which the genotype at one locus affects the expression of a gene at another locus. For example, an allele for a gene for black fur may mask the alleles at another locus, no matter which alleles are present at that locus.