Abstract
The knowledge of the genetic composition and relationships among livestock breeds is a necessary step for the implementation of management and conservation plans. This study aims to characterise the genetic diversity and relationships among six sheep breeds of meat aptitude that are spread through the eastern Pyrenees: Tarasconnaise, Castillonnaise and Rouge du Roussillon from France, and Aranesa, Xisqueta and Ripollesa from Spain. All but Tarasconnaise are catalogued as endangered. These breeds do not share the same ancestral origin but commercial trades and gene flow between herds are known to have occurred for centuries. Additionally, two outgroup breeds were included: the Guirra, from a different geographical location, and the Lacaune, a highly selected breed of dairy aptitude. A total of 410 individuals were typed using a panel of 12 microsatellite markers. Statistical, phylogenetic and Bayesian analyses showed that eastern Pyrenean breeds retained high levels of genetic diversity and low, but significant, levels of genetic differentiation (FST = 4.1%). While outgroups were clearly differentiated from other breeds, Pyrenean breeds tended to form two clusters. The first encompassed Tarasconnaise and Aranesa, which probably descend from a common meta-population. The second tended to group the other four breeds. However, none reached high mean Q-values of membership to a discrete cluster. This is consistent with the recent past gene flow between breeds, despite different ancestral genetic origins. The genetic characterisation carried out of the eastern Pyrenean sheep populations provides useful information to support decision making on their conservation and focusing efforts and resources to more singular breeds.
Highlights
Genetic documentation of existing livestock breeds enables the sustainable management and conservation of domestic animal diversity (FAO, 2009)
This study aims to characterise the genetic diversity and relationships among six sheep breeds of meat aptitude that are spread through the eastern Pyrenees: Tarasconnaise, Castillonnaise and Rouge du Roussillon from France, and Aranesa, Xisqueta and Ripollesa from Spain
Handley et al (2007) argue that, when compared with Northern European populations, Southern European sheep breeds keep higher genetic diversity due to their usually higher census sizes and the strong trading movement that Southern sheep populations have experienced during centuries
Summary
Genetic documentation of existing livestock breeds enables the sustainable management and conservation of domestic animal diversity (FAO, 2009). The characterisation of genetic diversity is one of the key points to match future demands of the agri-food markets (Ajmone-Marsan & Globaldiv Consortium, 2010). Molecular techniques (e.g. based on microsatellite markers) can be used to assess within-population genetic diversity and between-population differentiation and, make inferences on the degree of uniqueness of the analysed populations (Groeneveld et al, 2010). Together with the overviews of the sheep genetics scenario in the whole continent (Handley et al, 2007; Peter et al, 2007), during the last decade, such studies have become frequent in European sheep, both considering those sheep breeds spread in a given geographical area Ferrando et al / Span J Agric Res (2014) 12(4): 1029-1037
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