The genetic structure of English villages: surname diversity changes between 1976 and 1997

OBJECTIVE: To examine the change in the coefficient of relationship by isonymy (Ri) over a 21-year period. RESEARCH DESIGN: Ri was calculated from the surnames of males in the registers of electors for 15 villages near Oxford in 1976 and again in 1997. The within-residence component reflected the number of adult men of the same surname resident at the same address while the between-resident component of Ri was calculated by counting only one name of any surname at each address listed in the registers. RESULTS: Ri tended to decrease during the 21-year-period in 14 of the 15 villages and the between-resident component of Ri also tended to decrease in 14 of the villages. The within-residence component decreased in a statistically non-significant proportion (11 of the 15 villages). CONCLUSIONS: This study, in keeping with some but not all other surveys, showed that there was a tendency for random isonymy to decline in the 20th century. The reduction in the between-residence component can be accounted for by migration into the villages.