Inbreeding in Ojeda and Pernia, 1875-1985, province of Palencia, Spain.

The degree of isolation was assessed in two contrasting regions in Northern Palencia, Spain, one mountainous with small villages in the valleys (Pernia), the other lower and more open (Ojeda), with corresponding differences in economy. Using data from the parish and diocesan records, the frequencies of consanguineous marriages were calculated from the dispensation data, and the evolution of inbreeding compared. The more isolated region shows a greater degree of inbreeding, though not as high as in some other parts of Spain. Both regions show a decline in inbreeding with time, though in neither did the results indicate that geographic isolation was very outstanding. The most frequent types of consanguineous unions occur between second cousins.