Tracking diversity and differentiation in six sheep breeds from the North Iberian Peninsula through DNA variation

The classification of sheep breeds based on morphological traits alone is not always in agreement with historical and/or genetic data. In the present work, the genetic variability and relationship among six native ovine breeds from the northern part of the Iberian Peninsula were analyzed using eleven microsatellite markers. Additionally, assessment of the intra-population diversity of the Latxa breed was based on morphologically established varieties and types. Results from this study emphasize the importance of population structure within the Latxa breed and, in this sense, genetic data suggest a new classification of Latxa subpopulations. Multivariate analyzes performed made apparent branch differentiation among Latxa, Carranzana and Sasi Ardi breeds belonging to the churro branch and the Navarra, Rasa Aragonesa and Castellana breeds classified in the entrefino group. Large diversity within the churro branch in comparison to the more homogenous entrefino sheep was evident using neutral information based on molecular markers. These results, together with historical and morphological data, lead us to suggest the independent origin of the two groups from different migration events, followed by a highly differentiated demographic and reproductive history of the churro and entrefino branches. This study is an example of the usefulness of DNA variation analyzes applied to livestock for the assessment of the ethnological history of closely-related populations. © 2003 Published by Elsevier B.V.