Attempts to collect and analyze regional data often comprise a major part of the activities of government statistical offices. Tomaney, in International Encyclopedia of Human Geography, 2009 Cartographic RegionĪlmost all states collect statistical data on a regional basis to aid planning and administration. Remarkably, the abundant genetic diversity found in natural populations of plants and animals provides immense genetic resources for crop improvement in agriculture, biotechnology, and gene therapy in medicine. Similar conclusions-that is, that natural selection on allozyme polymorphism may be intense with selection coefficients in the range of 0.1–0.8-have also been reached for many model organisms ( Mitton, 1997). Genetic diversity either in the inbreeding wild cereals aboveground or in outbreeding mole rats underground is primarily determined by climatic selection. Similar results were obtained in extensive ecological genetic studies in wild wheat in 1989 by Nevo and Beiles and in subterranean mole rats across the Near East and Asia Minor ( Nevo, 1999). Our results suggest that natural selection, through environmental range and stress, in space or time or both appears to be an important genetic differentiating evolutionary force at the protein and DNA levels (i.e., driving molecular evolution) ( Nevo, 1998). Our results are clearly inconsistent with the genetic drift theory postulated in 1931 by Sewall Wright or the neutral theory of molecular evolution, even in its milder form of near neutrality ( Ohta and Gillespie, 1996). This contradicts a basic postulate of neutrality theory, which predicts positive correlation between H and N e ( Kimura, 1983). Notably, in the regional Israeli studies, heterozygosity, H, is negatively correlated with effective population size, N e H increases, whereas N e declines drastically toward the deserts. This result corroborates the environmental theory of genetic diversity, which regards ecological heterogeneity and stress as major determinants enhancing genetic divergence. Similar trends were found for several DNA systems in subterranean mole rats in Israel ( Nevo, 1999). Observed average heterozygosity, H, and gene diversity, H e, were positively and overall significantly correlated with rainfall variation, which is lowest in the northwest and highest in southern deserts (i.e., with a wider, fluctuating, climatic temporal niche in the desert) ( Figure 3). We found genetic parallelism across most taxa and most loci. These species varied in population size and structure, life histories, and biogeographical origins, but they largely shared geographically short and ecologically stressful gradients of increasing aridity in Israel, both eastward (70 km) toward the Syrian and Jordanian deserts and (mainly) southward (260 km) towards the Negev desert. 35: 229–245).Įach individual, population, and species were tested, on average, for 27 enzymatic gene loci. tali (reproduced from Nevo E and Beiles A (1988) Genetic parallelism of protein polymorphism in nature: Ecological test of the neutral theory of molecular evolution. See Broza et al., 1998, cited in Nevo, 1999. The only change is that Gryllotalpa gryllotalpa has been divided into two species, G. The average regression line is H e=−0.0556+0.4803 RV. Parallel genetic patterns in the level of gene diversity, H e, of 13 enzymatic systems averaged across all taxa studied here.
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