Hui Zhou (2014-07-18 16:14) Jilin University
Archaeological and anthropological investigations have helped to formulate two main theories to account for the origin of the populations in the Tarim Basin. The first, so-called “steppe hypothesis”, maintains that the earliest settlers may have been nomadic herders of the Afanasievo culture (ca. 3300-2000 B.C.), a primarily pastoralist culture distributed in the Eastern Kazakhstan, Altai, and Minusinsk regions of the steppe north of the Tarim Basin. The second model, known as the “Bactrian oasis hypothesis”, it maintains that the first settlers were farmers of the Oxus civilization (ca. 2200-1500 B.C.) west of Xinjiang in Uzbekistan, Afghanistan, and Turkmenistan. These contrasting models can be tested using DNA recovered from archaeological bones. Xiaohe cemetery contains the oldest and best-preserved mummies so far discovered in the Tarim Basin, possible those of the earliest people to settle the region. Genetic analysis of these mummies can provide data to elucidate the affinities of the earliest inhabitants.
Our results show that Xiaohe settlers carried Hg R1a1 in paternal lineages, and Hgs H, K, C4, M*in maternal lineages. Though Hg R1a1a is found at highest frequency in both Europe and South Asia, Xiaohe R1a1a more likely originate from Europe because of it not belonging to R1a1a-Z93 branch (our recently unpublished data) which is mainly found in Asians. mtDNA Hgs H, K, C4 primarily distributed in northern Eurasians. Though H, K, C4 also presence in modern south Asian, they immigrated into South Asian recently from nearby populations, such as Near East , East Asia and Central Asia, and the frequency is obviously lower than that of northern Eurasian. Furthermore, all of the shared sequences of the Xiaohe haplotypes H and C4 were distributed in northern Eurasians. Haplotype 223-304 in Xiaohe people was shared by Indian. However, these sequences were attributed to HgM25 in India, and in our study it was not HgM25 by scanning the mtDNA code region. Therefore, our DNA results didn't supported Clyde Winters’s opinion but supported the “steppe hypothesis”. Moreover, the culture of Xiaohe is similar with the Afanasievo culture. Afanasievo culture was mainly distributed in the Eastern Kazakhstan, Altai, and Minusinsk regions, and didn’t spread into India. This further maintains the “steppe hypothesis”.
In addition, our data was misunderstand by Clyde Winters. Firstly, the human remains of the Xiaohe site have no relation with the Loulan mummy. The Xiaohe site and Loulan site are two different archaeological sites with 175km distances. Xiaohe site, radiocarbon dated ranging from 4000 to 3500 years before present, was a Bronze Age site, and Loulan site, dated to about 2000 years before present. Secondly, Hgs H and K are the mtDNA haplogroups not the Y chromosome haplogroups in our study. Thirdly, the origin of Xiaohe people in here means tracing the most recently common ancestor, and Africans were remote ancestor of modern people.
