Some genetical inferences from the marriage system of Reading, Berkshire, and its surround area

A survey of marriages celebrated in 1972/73 in Reading, Berkshire, and its urban field was carried out in 1974. It provided information about the birthplace of husband and wife and of their parents, about their joint home after marriage, and on their social class origins. These data were used to produce a migration-matrix showing the probability of movement from one part of the area (and the outside world) to all the other parts of the area. A modification of the iterative deterministic model of Hiorns et al. (1969) permitted estimates to be made of the number of generations which would elapse before all the subdivisions of the survey area shared 95% of the same ancestry, assuming an initial state of zero relatedness between them and the continuation of current patterns of marital mobility. Without contributions from the 'outside world', the 18 subdivisions of the survey area become ancestrally homogeneous with each other within 3--15 generations, while with contributions from the 'outside world', the process takes not more than six generations. Marriages between social classes combined with intergeneration social mobility make the ancestry of these classes homogeneous after four generations at most.