Genetics of Natural Populations XXVII The Genetic Changes in Populations of Drosophila pseudoobscura in the American Southwest
Dobzhansky T. 1958. Genetics of Natural Populations XXVII The Genetic Changes in Populations of Drosophila pseudoobscura in the American Southwest. Evolution. 12(3):385-401
This article concerns the genetics of free-living populations of a desert species of fruit-fly (Drosophila pseudoobscura). The original populations studied are from similar environmental conditions, in mountain forests of the Death Valley region, but isolated from each other. This paper reports on continuing experiments, now expanded to include samples from other regions. Data from Death Valley (Panamint Mountains) samples is included. The paper states that the genetic composition of some species can change from year to year, or even season to season, and provides details about the changes. Data are presented showing that populations of Drosophila pseudoobscura of ten localities in different parts of California have changed between 1940 and 1957 in the same direction-appearance and increase of the frequencies of chromosomes with PP gene arrangement and decrease of chromosomes with CH gene arrangement. Since PP chromosomes are most prevalent in the populations of Texas and of the eastern slope of the Rocky Mountains, it is important to note that no appreciable increases in the frequencies of PP have taken place in nine of the ten localities in Arizona and Utah for which samples taken in 1940 (or 1941) and in 1957 are available. The causes which have brought about the genetic changes in the California populations are unknown. The changes seem not to be provoked by human interference with the habitats of the flies; at any rate, the changes are no greater in localities close to the regions of greatest concentration of human populations than in localities far from such regions.
- Type
- Journal Article
- Authors
- Dobzhansky, Theodosius
- Units
- DEVA
- Keywords
- Absence (Biodiversity), Animal Studies, Death Valley National Park CA NV, Distribution (Biodiversity), Drosophila pseudoobscura (Diptera: Drosophilidae), Genetic Studies, insect survey, Panamint Mountains, Presence (Biodiversity), Taxa Links To Datasets, Taxa Links To References, Terrestrial Invertebrates