Livestock genetic origins: goats buck the trend.

T domestic goat (Capra hircus) often is dismissed as the ‘‘poor man’s cow’’ for its ability to thrive on meager fodder and cope with harsh environments. However, this belies the economic and archaeological importance of the species. From an agricultural standpoint, the world’s 700 million goats provide reliable access to meat, milk, skins, and fiber for small farmers—particularly in developing countries. In addition, accumulating archaeological evidence indicates that goats, in the form of their wild progenitor—the bezoar (Capra aegagrus), were the first wild herbivores to be domesticated (Fig. 1). These studies suggest that this happened '10,000 years ago at the dawn of the Neolithic in the region known as the Fertile Crescent (1, 2). Therefore these sturdy animals may have been the first ‘‘walking larders’’ and by example, could have triggered subsequent domestications of the full repertoire of Euroasian livestock species that have provided the bulk of the animal protein consumed by ever-expanding human populations. In this issue of PNAS, Luikart and colleagues (3) add C. hircus to the growing list of domestic animals that have been widely surveyed for mtDNA sequence variation (4–9). In their survey, Luikart et al. (3) demonstrate that the structure and distribution of mtDNA variation in domestic goats are qualitatively different from the patterns observed in other large Eurasian herbivores domesticated for food, skins and fiber (cattle, buffalo, pigs, and sheep; see Fig. 2).