Genetic relationship amongst the major non-coding regions of mitochondrialDNAs in wild boars and several breeds of domesticated pigs

We completed phylogenetic analysis of the major non-coding region of the mi tochondrial DNA (mtDNA) from 159 animals of eight Euro-American and six Eas t Asian domesticated pig breeds and 164 Japanese and five European wild boa rs. A total of 62 mtDNA haplotypes were detected. Alignment of these region s revealed nucleotide variations (including gaps) at 73 positions, includin g 58 sites with transition nucleotide substitutions, and two transversion s ubstitutions. Phylogenetic analysis of the sequences could not organize dom estic pig breeds into discrete clusters. In addition, many of the haplotype s found in members of diverged clustering groups were found primarily in Eu ro-American pig breeds, indicating extensive introgression of Asian domesti c pigs into European breeds. Furthermore, phylogenetic analysis allocated t he DNA sequences of non-coding regions into two different groups, and the d eepest branchpoint of this porcine phylogeny corresponded to 86 000-136 000 years before present. This time of divergence would predate the historical period when the pig is thought to have been domesticated from the wild boa r.