Publications by authors named "Maria Jose Blanco-Villegas"

Since domestication, a large number of livestock breeds adapted to local conditions have been created by natural and artificial selection, representing one of the most powerful ways in which human groups have constructed niches to meet their need. Although many authors have described local breeds as the result of culturally and environmentally mediated processes, this study, located in mainland Spain, is the first aimed at identifying and quantifying the environmental and human contributions to the spatial structure of local breed diversity, which we refer to as livestock niche. We found that the more similar two provinces were in terms of human population, ecological characteristics, historical ties, and geographic distance, the more similar the composition of local breeds in their territories.

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In a previous study concerning 33,753 single Spanish surnames (considered as tokens) occurring 51,419,788 times we have shown that the present-day geography of contemporary surname variability in Spain still corresponds to the political geography of the country at the end of the Middle Ages. Here we reprocess the same database, by clustering surnames with Self-Organizing Maps (SOMs) according to their geographic distribution, to identify the monophyletic surnames showing a geo-historical origin in one of the 47 provinces of continental Spain. They are 25,714, and they occur 12,348,109 times, meaning that about 75% of the Spanish population bears a surname that had a polyphyletic origin.

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To assess whether the present-day geographical variability of Spanish surnames mirrors historical phenomena occurred at the times of their introduction (13th-16th century), and to infer the possible effect of foreign immigration (about 11% of present-day) on the observed patterns of diversity, we have analyzed the frequency distribution of 33,753 unique surnames (tokens) occurring 51,419,788 times, according to the list of Spanish residents of the year 2008. Isonymy measures and surname distances have been computed for, and between, the 47 mainland Spanish provinces and compared to a numerical classification of corresponding language varieties spoken in Spain. The comparison of the two bootstrap consensus trees, representing surname and linguistic variability, suggests a similar picture; major clusters are located in the east (Aragón, Cataluña, Valencia), and in the north of the country (Asturias, Galicia, León).

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In this work the level and structure of consanguinity is analysed in two Spanish rural regions of similar geographic and orographic characteristics for the period between 1880 and 1979, employing two different methodologies. The estimates according dispensations shows that the total levels (alpha4 = 0.00552 in La Cabrera and 0.

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The biodemography of isolated populations with a subsistence economy is of special interest because the conditions to which the populations have been subjected are similar to those present over a large part of the history of our species, and hence the conclusions drawn can be extrapolated to other similar populations. In the present work, we used two recently employed techniques (self-organizing maps and Monmonier's algorithm) to study the genetic structure of a small rural region: Fuentes Carrionas (province of Palencia, Spain). The study was based on information contained in marriage registers and family reconstructions for the period 1880-1979.

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The genetic structure of La Cabrera (province of Léon, Spain), a highly isolated and inbred population (alpha3 = 0.00482), is analyzed by applying multivariate methods (nonmetric multidimensional scaling, Mantel test, Monmonier's algorithm) to different biodemographic data sets. Isonymy, parent-offspring migration (total, males, females), and marital migration matrices were obtained from 5,714 marriages recorded in 37 parishes (clustered in 4 municipalities) between 1880 and 1989.

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La Cabrera (northwest Spain), the study area, during most of the period examined (1880-1969) was characterized by high inbreeding levels and internal subdivision, which probably favoured the action of genetic drift and genetic differentiation. Indices regarding potential selection based on variables related to the reproductive pattern of reconstituted families with complete reproductive cycles (n = 1498) were analysed. A traditional demographic context, characterized by a reduction of mortality resulting in the remarkable increase of number of survivors to reproductive age, is distinguished from a recent context in which survival was similar (approximately 89%) and the fall of mortality and natality proportional.

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Biodemographic methods are widely used to infer the genetic structure of human populations. In this study, we revise and standardize the procedures required by the migration matrix model of Malécot ([1950] Ann Univ Lyon Sci [A] 13:37-60), testing it in large historical-demographic databases of 85 populations from three mountain valleys with different degrees of isolation: Val di Lima (Italian Apennines, 21 parishes), Val di Sole, (Italian Alps, 27 parishes), and La Cabrera (Spain, 37 parishes). An add-on package (Biodem) for the R program is proposed to perform all calculations.

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Marital structure and inbreeding coefficients were analyzed in La Cabrera, an isolated mountain region in northwestern Spain. A total of 5,714 marriages were celebrated from 1880 to 1989 in the 37 parishes of the area. The total frequency of consanguineous marriages (up to the fourth degree) is 23.

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