Showing papers on "Isolation by distance published in 1971"

An Investigation of the Isolation-By-Distance Model

Abstract: Wright's isolation-by-distance model was investigated using techniques of simulation on a digital computer. We examined the manner in which a population as a whole differentiated in time, as well as the distributional pattern of gene frequencies in the population. Both the areal and the linear isolation-by-distance models were investigated. The observed rate of increase in the inbreeding coefficient did not agree well with that predicted by the results of Wright (although the differences may be due to changes which take place in only the first few generations). It was also found that the particular patterns of highs and lows of gene frequencies over a geographic area became established quickly and persisted for a large number of generations, particularly near the periphery of the population. Implications of our results for interpreting geographic variation analyses in terms of differential selection are discussed.

Isolation by Distance in Bougainville

Abstract: The technique of population structure analysis based upon the model of Malecot is applied to blood polymorph, anthropometric, and demographic data collected from residents of south-central Bougainville Island, Territory of New Guinea. The results from these several analyses are relatively consistent and support the idea that this theoretical model can be applied successfully to real sets of biological data and that useful conclusions can be reached concerning the breeding structure of human populations. A comparison of population structures from various parts of the world reveals how fragmented the breeding structure in Melanesia is, and how relatively rapidly the coefficient of kinship declines over distance in that area.

The variation problem: the gene flow-variation

Abstract: Summary Phenotypic variation is as poorly understood as it is ubiquitous. Many biologists hold simplistic and even contradictory views of the relation between genic diversity and phenotypic variation. The correlation of electrophoretically detectable enzyme polymorphisms and morphological variation in island populations of lizards is described. A model explaining the different levels of genetic-phenetic variation among the populations is suggested by a multiple regression analysis. The principal conclusions are that gene flow between habitats significantly elevates variation, and isolation by distance results in a variation asymptote.