Inbreeding and population subdivision in Córdoba province, Argentina, at the end of the eighteenth century.
Centro de Estudios Avanzados, UE, CONICET-Universidad Nacional de Córdoba, Argentina.Journal of Biosocial Science (Impact Factor: 0.98). 05/2011; 43(6):717-32. DOI: 10.1017/S0021932011000174
Marital isonymy is frequently used to estimate inbreeding and the repeated pairs method is useful to investigate whether the population under examination has subdivisions. These methods can also be applied to registers, such as population censuses, where both spouses' surnames are noted. In this paper, the 1795 census for Córdoba province is analysed. Numerically speaking, Spanish and mixed-race people are the major ethno-social groups in the register. In order to estimate inbreeding, the isonymic method was applied to both groups, at provincial and at parish level. To appreciate to what extent the parishes were genetically isolated, Wright's Fst was also calculated. The repeated pairs method was also used for both groups to assess if population subdivision existed in the units under study. Finally, to evaluate whether the subdivision based on surnames reflected the ethno-social stratification, the same method was used considering the two groups together. At the provincial scale, both groups displayed low inbreeding and micro-differentiation, although the former was higher for the Spanish and the latter for mixed-race groups, which could indicate a more marked conjugal selectivity in the Spanish. At the parish scale, preferences for isonymic spouses were not pronounced either in Spanish or in mixed-race groups; in the Spanish group population subdivision prevailed, with the opposite occurring in the mixed-race group. The estimations from repeated pairs, taking the two groups together, indicated that for the studied populations the surnames do not allow the two groups to be differentiated into isolated reproductive units.
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ABSTRACT: Married couples in Córdoba City (Argentina) were studied from the census data of 1778, 1795, 1813, 1822, and 1832. Homogamy regarding ethnic group, juridical status, and the title "Don/Doña" was analyzed through contingence coefficients as well as inbreeding and mate preferences among lineages, using the isonymy and repeated pair methods. Class endogamy was revealed in all groups and homogamy was found for various characteristics. The inbreeding was low, but repeated pairs of surnames indicated associated family lines in the Spanish group. A temporal analysis showed that both indicators were higher in times of sociopolitical instability.
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ABSTRACT: The study of surnames in a territory over time is an opportunity to obtain knowledge of the evolution of allelic frequencies. Geographic and cultural factors influence the renovation of surnames and reflect accelerations or delays in the gene flow. Political borders may also condition the genetic structure of a population. Using isonymy, this paper studies the evolution (from 1750 to 2006) of the frequencies of surnames and the components of inbreeding in Olivenza, a border town whose sovereignty was transferred from Portugal to Spain in 1801. After the change in dominion the number of Portuguese surnames fell sharply and the expected values for a population so close to Portugal recovered only after a long period of time. The results indicate that although the border has made population movement more difficult, and has therefore had an impact on the rate of gene exchange, a certain gene flow with Portugal persisted.
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