What does polymorphism in genetics refer to?

Polymorphism in genetics refers to the existence of multiple forms or alleles at a particular gene locus within a population. This variation allows for diversity in traits among individuals, which is essential for the process of evolution and can lead to differences in phenotypes. When multiple alleles are present, it increases the genetic diversity within the population, making it more adaptable to changes in the environment.

Having multiple alleles at a locus can result in a range of traits, which is often observed in characteristics such as flower color or blood type in humans. This genetic variability is crucial for natural selection, as it provides the raw material for evolutionary processes.

In contrast, the other options denote different concepts in genetics, such as the lack of variation, the gradual change in allele frequencies (which relates to evolution and population genetics), and gene cloning, none of which accurately capture the meaning of polymorphism.