Abstract :
The aim of the present study was to estimate the genetic intra-breed variability of Churra
tensina and Churra lebrijana endangered breeds and to establish genetic relationships with
Churra, Latxa and Merino breeds, as well as Spanish mouflon, by using 28 microsatellite
markers, to provide useful information for their conservation. Allele frequencies and heterozygosity
revealed high genetic variation in the two endangered breeds despite their
small population size. Estimates of inbreeding coefficient (FIS) were significant for all breeds
studied, except for Churra lebrijana breed. The highest inbreeding coefficient (FIS = 0.143)
was found in the Spanish mouflon. Genetic differentiation tests (FST = 0.121) and assignment
of individuals to populations indicated the existence of defined breed populations, and low
genetic flow between these breeds. The highest pairwise Reynolds distance (DR) values
were observed between Mouflon and the domestic sheep breeds. Considering only domestic
sheep breeds, the Churra lebrijana breed showed the highest pairwise DR values. The
lowest values were found between Latxa and the other domestic sheep, except for Churra
lebrijana. Results of pairwise DR values, as well as phylogenetic tree and bottleneck analysis
showed an important genetic isolation of the Churra lebrijana breed from the other Churra
types, and genetic signatures of a demographic bottleneck. Finally, structure analysis of
populations detected a population subdivision in the Latxa sheep breed. In conclusion, this
study presents valuable insight into the existing genetic variability of two Spanish endangered
breeds, as well as the first study in Spanish mouflon based on microsatellite analysis.
The high degree of variability demonstrated in Churra tensina and Churra lebrijana implies
that these populations are rich reservoirs of genetic diversity
