Inbreeding, marital movement, and genetic isolation of a rural Appalachian population

Genealogical, marital, birthplace and age-at-marriage data were collected on a random sample of 275 reproducing couples from the population of a rural Appalachian county in north-eastern Tennessee. Genealogies covering the three extant generations provided the data for a surname isonymy analysis to determine the amount of inbreeding prevalent, while the marital, birthplace and age at marriage data were used to ascertain the components of marital movement, i.e., marital distance, orientation of marital movement, spatial exogamy, and "diffusion". The effective breeding population and effective immigration rate were calculated for the county population and these in turn were used to compute the coefficient of breeding isolation for the currently reproduction population. Our conclusions agree with those of an earlier genetic and demographic study on one segment of the same population. The more extensive demographic analysis illustrates the value of such studies as this for providing background for interpretations of genetic variation.