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.
Because the transmission of genes from one generation to the next is fundamentally a demographic process, the size of the population is an integral part of almost any population genetics analysis. Put differently, genetic drift is directly related to population size (small = more drift, large = less drift).