Multiple maternal origins and weak phylogeographic structure in domestic goats

Domestic animals have played a key role in human history. Despite their imp ortance, however, the origins of most domestic species remain poorly unders tood. We assessed the phylogenetic history and population structure of dome stic goats by sequencing a hypervariable segment (481 bp) of the mtDNA cont rol region from 406 goats representing 88 breeds distributed across the Old World, Phylogeographic analysis revealed three highly divergent goat linea ges (estimated divergence > 200,000 years ago), with one lineage occurring only in eastern and southern Asia. A remarkably similar pattern exists in c attle, sheep, and pigs. These results, combined with recent archaeological findings, suggest that goats and other farm animals have multiple maternal origins with a possible center of origin in Asia, as well as in the Fertile Crescent. The pattern of goat mtDNA diversity suggests that all three line ages have undergone population expansions, but that the expansion was relat ively recent for two of the lineages (including the Asian lineage). Goat po pulations are surprisingly less genetically structured than cattle populati ons. In goats only approximate to 10% of the mtDNA variation is partitioned among continents. In cattle the amount is greater than or equal to 50%. Th is weak structuring suggests extensive intercontinental transportation of g oats and has intriguing implications about the importance of goats in histo rical human migrations and commerce.