INFERENCE ON GENETIC STRUCTURE FROM POTENTIAL MATES ANALYSIS, A STUDY OF TWO HISTORICAL POPULATIONS (ANTHROPOLOGY, DEMOGRAPHY)

• Main Author: GRADIE, MARGARET ISABEL
• Language: ENG
• Published: ScholarWorks@UMass Amherst 1986
• Subjects: Physical anthropology
• Online Access: https://scholarworks.umass.edu/dissertations/AAI8612041

The objective of this research is to better understand the number of potential mates as a variable for analyzing the processes which lead to genetic structure. To do this, variation in the number of potential mates over space and time is examined. In particular, the effects of demographic change, geographic location, and kinship within the mate pool are examined for their influence on the size of the mate pool, mating patterns, and genetic structure, in two historical populations. The method compares the effects of these variables in populations with different geographic structures, but similar histories of population growth and decline. The geographic difference is relevant since most potential mates analysis has been applied to island isolates. The similarity in demographic history is important since it allows some control over between-population comparisons. The study populations are North Ronaldsay, one of the Orkney Islands located off the east coast of Scotland, and Ashfield, Massachusetts, a town in the Connecticut River Valley. These populations fill the requirements of the study in that they share similar demographic histories, but are different in geographic characteristics. The expectations represent a null hypothesis that both populations should look the same. The results show that change in numbers of potential mates over time is not strictly related to change in population size, but responds to changes in the age range in which males enter the mate pool. These changes are not the result of distortions in the age-sex structure. There is considerable variation between individuals in their numbers of available mates in all time periods in both populations. North Ronaldsay shows very little intermarriage with neighboring populations, while in Ashfield geographically close populations contribute a significant number to the mate pool. Individuals who fail to marry on North Ronaldsay do not appear to have a larger proportion of kin as potential mates. In fact, there appear to be distinct mating preferences for some categories of kin. In Ashfield, very little kinship within the mate pool is observed. This is consistent with other studies of kinship in Connecticut Valley towns.