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.
Understanding the Mathematics of Drift. To get a feel for genetic drift, consider a population at for a gene with two , A and a. Let p = the relative of the A , let q = the relative frequency of the a allele, and let p = q = 0.5. For no drift to occur, the frequencies of the alleles in successive generations must remain at 0.5.