Some radioactive iodide salts of sodium, including [ 125I ]NaI and [ 131I ]NaI, have radiopharmaceutical uses, such as in the treatment of thyroid cancer and hyperthyroidism or as radiolabeling tracers in imaging (see).
Genetic drift is defined as the changing of the number of available alleles in a population by chance events. Also called allelic drift, this phenomenon is usually due to a very small gene pool or population size.
A population's allele frequency is the fraction of the copies of one gene that share a particular form.[3] Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. When there are few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller.