Origins and propagation routes of South/Southeast Asian goats analyzed by DNA information Available to Purchase

Goats were one of the oldest domesticated ruminants and are thought to have been domesticated in the mountains of West Asia between 7000 and 10,000 BC. The earliest evidence for its domestication was the discovery of relics in a supposedly >7,000 B.C. on the coast of the Yerko and Caspian Seas, Jordan. Goats are also remarkable in that they are bred all over the world in the exception of quite cold regions such as the Arctic. About 75% of the world’s population uses goat for milk, meat, wool, and/or leather. Existing wild goats are roughly classified into three subspecies: Bezoar (Capra aegagrus), distributed in West Asia; Markhor (C. falconeri), inhabiting Afghanistan and Pakistan; and Ibex (C. ibex), scattered in West Asia, Central Asia, East Africa, and Europe. Among these, Bezoar is the most widely agreed wild goat, and in addition, genetic effects of Markhor in the Central Asian region and genetic effects of Ibex in the course of transmission to the African region are suggested. The world’s domestic goats are broadly classified into three categories as Bezoar type, Savanna type, and Nubian type. Recently, DNA polymorphism analyses for goats have been performed, especially using the D-loop region of mitochondrial DNA (mtDNA). As a result, it has been clarified as six haplogroups (types A-G). The divergence times among these haplogroups were estimated to be at least >50,000 years, suggesting that they diverged before domestication. However, analyses of multiple strains of wild goats Bezoar, Markhor, and Ibex are genetically distinct from the haplotypes of these domestic goats, and from this analysis, it is not clear from which wild goats they are inherited from their ancestors or genetic influences. The mitochondrial haplogroup A predominates in most of the world, and is almost exclusively found in Europe and Africa, especially in the Middle East and the West. On the other hand, the mitochondrial haplogroup B is found in more eastern countries, particularly in Southeast Asia at high frequency, and its frequency tends to increase in the southeast. The fact that this type B is restricted to East Asia and is more frequent in Southeast Asian countries may provide interesting insights into the domestication and propagation routes of goats. In addition, SRY 3 UTR sequences on Y chromosome revealed four major SRY haplotypes (Y1A, Y1B, Y2A, and Y2B) with a marked geographic differentiation and several regional variants. The haplotypes Y1A and Y2A are found worldwide at high frequencies, whereas the haplotypes Y1B and Y2B are found specifically in Europe and Southeast Asia, respectively. Moreover, whole-genome sequences showed that the Y1A haplotype was split into Y1AA and Y1AB. Subsequently, we examined genome-wide analysis of modern Eurasian goats using goat 52K SNP array for estimating the genetic structure and the establishing process of Southeast Asian goats. The results of the analyses in Asian goat populations were well matched with topology of geographical locations, suggesting two major propagation routes from domestication center to Southeast Asia via Southwest Asia and Northeast Asia via Central Asia. The genome-wide SNP information in addition of uniparental markers could supply a comprehensive scenario of Southeast Asian goat history. In this ICAST4 conference, I would like to talk about our results based on molecular evidence and discuss the origin(s) and propagation route(s) in the East and Southeast Asian goats.