Abstract :
The aim of this study was to analyze, through the use of microsatellite molecular markers,
the genetic diversity and variability of nine Alpine sheep breeds reared in Italy (Bergamasca,
Biellese, Schwarzbraunes Bergschaf, Tiroler Bergschaf, and Schnalserschaf), Germany
(Brillenschaf and Weisses Bergschaf) and Slovenia (Bovˇska and Jezerzkˇo-Solˇcavska), and
one Italian crossbreed population. Allelic richness was rather high in each breed highlighting
a considerable genetic diversity. However, the study evidenced a significant departure
from Hardy–Weinberg equilibrium in all analyzed breeds caused by a heterozygote deficiency.
Such lack seems to be caused both to the presence of population substructure within
breed and to a rather high level of inbreeding. The genetic differentiation among breedwas
rather low (FST = 0.057) but significant. The clustering analysis performed with STRUCTURE
detected the presence of eight clusters; Schwarzbraunes Bergschaf and Tiroler Bergschaf
were grouped together and Biellese and Bergamasca aswell, evidencing a high similarity of
their genetic make up. Reynolds’ genetic distance estimates confirmed the close relationship
between these pairs of breeds. Moreover, Bovˇska, Jezerzkˇo-Solˇcavska and Brillenschaf
resulted rather similar as expected according to their region of origin and to their common
ancestors. Molecular coancestry confirmed as well such findings, suggesting that the
studied breeds had origin from different ancestral populations. Concluding, microsatellite
resulted a useful tool to investigate breed variability and to characterize Alpine sheep
breeds. Obtained findings suggest the need to set up a conservation plan aiming to safeguard
and increase the genetic variability of the studied breeds compromised by the high
level of inbreeding. Microsatellites genotyping could help to monitor breed variability and
to organize matings.
