Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Allele frequency refers to how common an allele is in a population. It is determined by counting how many times that allele appears within the population then dividing by total number of alleles for that gene.
An allele that expresses its phenotypic effect even when heterozygous with a recessive allele; it masks effects of recessive alleles - just like bright lights can outshine dimmer ones at concerts!
An allele whose characteristic only shows up when it is paired with a similar allele - like a dim light stick that can only be seen when the brighter ones are turned off.