The sequence and analysis of a Chinese pig genome

Our results reveal some unique genomic features, including a relatively high level of homozygosity in the diploid genome, an unusual distribution of heterozygosity, an over-representation of tRNA-derived transposable elements, a small amount of porcine endogenous retrovirus, and a lack of type C retroviruses. In addition, we carried out systematic research on gene evolution, together with a detailed investigation of the counterparts of human drug target genes.Our results provide the opportunity to more clearly define the genomic character of pig, which could enhance our ability to create more useful pig models.Domestic pigs belong to the mammalian clade Artiodactyla, a group of even-toed, hoofed animals whose extant representatives include ruminants such as cattle and sheep. In contrast to ruminants, pigs are omnivores and can easily adapt to changes in diet, and possess a digestive system that is simple, anatomically and physiologically distinct from ruminant stomachs. As one of the oldest forms of livestock, pigs were domesticated as early as 8,000-10,000 BC from Eurasian wild boars [1]. Pigs are commonly raised for meat, which is the most important animal protein food source, and feed a majority of the global population. Other pig derivatives include industrial materials such as pharmaceutical-grade heparin, which is mostly derived from mucosal tissues of the pig small intestine.Unlike other domesticated animals such as cattle and sheep, pigs were mainly raised in agricultural societies and settled farming communities, rather than by nomadic people. After a long period of breeding outdoors in yards or fields, pigs evolved eating patterns resembling those of human beings. The similarity dietary structure, as well as the close resemblance of pigs' digestive organs to those in humans (i.e., the stomach, pancreas and small intestine), enable pigs to develop digestion, nutrient absorption, metabolism and intestinal microflora in common with human beings. Pigs also sha