01380naa a2200169 a 450000100080000000500110000800800410001910000120006024500890007226000090016152009220017065000160109265300280110870000170113670000200115377300370117312800602025-07-10       1975    bl uuuu     u00u1 u    #d1 aNEI, M.  aThe bottleneck effect and genetic variability in populations.h[electronic resource]  c1975  aIn a population of constant size the expected heterozygosity for a neutral locus when mutation and genetic drift are balanced is given by 4 Nv/(4Nv + 1) under the assumption that new mutations are always different from the pre-existing alleles in the population, where N is the effective population size and v the mutation rate per locus per generation (Kimura, 1968). The size of a natural population, however, often changes drastically in the evolutionary process. In an extreme case a single inseminated female from a large population may migrate to an unoccupied geographical or ecological territory and establish a new colony, followed by rapid population growth to form a new species. This process seems to have occurred repeatedly in the evolution of Hawaiian Drosophila species (Carson, 1970; 1971) and also in the establishment of the Bogota, Colombia, population of Drosophila pseudoobscura (Prakash, 1972).  aPopulação  aVariabilidade genética1 aMARUYAMA, T.1 aCHAKRABORTY, R.  tEvolutiongv. 29, p. 1-10, 1975.