Domestication, modern breeding and artificial selection have shaped dramatically the genomic variability of domestic animals. In livestock, the so called FAT1 QTL in porcine chromosome 4 was the first quantitative locus (QTL) uncovered although, to date, its precise molecular nature has remained elusive. Here, we characterized the nucleotide variability of thirteen ~ 500 bp fragments equally spaced in a 2 Mb region in the vicinity of the FAT1 QTL in a wide diversity 32 pig panel. Asian and European animals, including local Mediterranean and international pig breeds were sequenced. Patterns of genetic variability were very complex and varied largely across loci and populations; they did not reveal overall a clear signal of a selective sweep in any breed, although FABP4 fragment exhibited a significantly higher diversity. We employed an approximate Bayesian Computation approach to infer the evolutionary history of this SSC4 region. Notably we found that European pig populations have a much lower effective size than their Asian counterparts: in the order of hundreds vs. hundred of thousands, respectively. We show also an important part of extant European variability is actually due to introgression of Asian germplasm into Europe. This study shows how a potential loss in diversity caused by bottlenecks and possible selective sweeps associated with domestication and artificial selection can be counterbalanced by migration, making it much more difficult the identification of selection footprints based on naïve demographic assumptions. Given to the small fragment analysed here, it remains to be studied how these conclusions apply to the rest of the genome.
|Titolo:||Evolutionary study of a potential selection target region in the pig|
|Data di pubblicazione:||2011|
|Appare nelle tipologie:||1.1 Articolo in rivista|