SUMMARY Italy has a rich diversity in farm animals. In particular, Tuscany hosts a number of autochthonous bovine breeds that are, or have been, relevant for the economic sustainability of the agriculture, the origin and history of which are still poorly documented. Most of these breeds suffered in the past a dramatic loss of economic importance being substituted by cosmopolite and more productive breeds. The aim of the present study was to analyse levels of genetic diversity and relationship among local cattle breeds from Tuscany (Central ltaly) using microsatellite markers. DNA from 194 animals (Calvana, 6l; Garfagnina, 43; Pontremolese,2 3; Chianina, 67) was analyzeda t22 microsatellitel oci. Number of alleles( NA) and allelic frequenciesw ere estimated. Locus by locus F51, exact tests for deviations from the Hardy-Weinberg equilibrium (HWE) and pair-wise linkage disequilibrium (LD) among microsatellite loci were evaluated. In addition, various among-population genetic distances were calculated. The study evidenced a significant departure from Hardy-Weinberg equilibrium in all the analyzed breeds, probably causedb y a rather high level of inbreeding for Calvana,G arfagnina and Pontremolese,w hereasl ikely reflecting the results of recent selectivep rocessesin Chianina. The overall fixation index was 0.115+0.054.R esultso btained in this study suggestt hat the situation of the analyzed breeds is risky as their variability is compromised by a high level of inbreeding, in particular Pontremolese was the most compromised breed. Several distance metrics highlighted a only moderate differentiation between Chianina and Calvana if compared to values found among the other breeds. Also molecular coancestry and kinship distance supported the hypothesis that Calvana originated from Chianina, whereas Garfagnina and Pontremolese should have different ancestralo rigins. The low geneticv ariability suggeststh e need for a qareful geneticm anagemento f the breeds,i n order to maintain long-term population survival and adaptability and to avoid the risk of more excessivein creasei n the inbreeding level, which would result in significant inbreeding depression and in significant loss of genetic variation.
|Autori:||Cecchi F.; CIAMPOLINI R; Castellana E.; Ciani E.|
|Titolo:||Genetic diversity within and among endangered local cattle breeds from Tuscany (Italy).|
|Anno del prodotto:||2012|
|Appare nelle tipologie:||1.1 Articolo in rivista|