Which term describes the presence of two or more variants at a locus in a population at frequencies above the mutation rate?

The term that describes the presence of two or more variants at a locus in a population at frequencies above the mutation rate is polymorphism. This concept is crucial in genetics as it indicates genetic diversity within a population. A polymorphism occurs when there are multiple alleles at a particular gene locus that contribute to different traits and can be passed from one generation to another.

In contrast, haplotype refers to a combination of alleles at multiple loci that are transmitted together, which doesn’t specifically relate to the frequency of variants at a single locus. Genotype refers to the genetic makeup of an individual for a particular trait, while phenotype refers to the observable physical or biochemical characteristics of an organism as determined by both genetic makeup and environmental influences. Thus, polymorphism distinctly emphasizes the variety of alleles present in a population that exceeds the baseline mutation occurrence, highlighting significant genetic variation.