Major population expansion in mtDNA of East Asians

Table 2 has the expansion times.

PLoS ONE 6(10): e25835. doi:10.1371/journal.pone.0025835

Major Population Expansion of East Asians Began before Neolithic Time: Evidence of mtDNA Genomes

Hong-Xiang Zheng et al.

It is a major question in archaeology and anthropology whether human populations started to grow primarily after the advent of agriculture, i.e., the Neolithic time, especially in East Asia, which was one of the centers of ancient agricultural civilization. To answer this question requires an accurate estimation of the time of lineage expansion as well as that of population expansion in a population sample without ascertainment bias. In this study, we analyzed all available mtDNA genomes of East Asians ascertained by random sampling, a total of 367 complete mtDNA sequences generated by the 1000 Genome Project, including 249 Chinese (CHB, CHD, and CHS) and 118 Japanese (JPT). We found that major mtDNA lineages underwent expansions, all of which, except for two JPT-specific lineages, including D4, D4b2b, D4a, D4j, D5a2a, A, N9a, F1a1'4, F2, B4, B4a, G2a1 and M7b1'2'4, occurred before 10 kya, i.e., before the Neolithic time (symbolized by Dadiwan Culture at 7.9 kya) in East Asia. Consistent to this observation, the further analysis showed that the population expansion in East Asia started at 13 kya and lasted until 4 kya. The results suggest that the population growth in East Asia constituted a need for the introduction of agriculture and might be one of the driving forces that led to the further development of agriculture.

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Ancient mtDNA of Hokkaido Jomon

This is a very good paper that I don't have time right now to write a long post about; I will update this entry with some excerpts and/or additional thoughts when I can.

The gist of it is that the prehistoric Jomon people of Japan belonged to mtDNA haplogroups tying them to southeastern Siberia, but some haplogroups present there today were lacking in them. Then, the Ainu seem to have inherited the Jomon gene pool, but their major lineages tie them to the Okhotsk people. So, it seems that the deepest ancestry of Japan is not peculiar to it, but rather an extension of ancient Siberian variation with different population strata attributed to the Jomon, the Ainu, and (probably) the modern Japanese.

AJPA DOI: 10.1002/ajpa.21561

Mitochondrial DNA analysis of Hokkaido Jomon skeletons: Remnants of archaic maternal lineages at the southwestern edge of former Beringia

Noboru Adachi et al.

To clarify the colonizing process of East/Northeast Asia as well as the peopling of the Americas, identifying the genetic characteristics of Paleolithic Siberians is indispensable. However, no genetic information on the Paleolithic Siberians has hitherto been reported. In the present study, we analyzed ancient DNA recovered from Jomon skeletons excavated from the northernmost island of Japan, Hokkaido, which was connected with southern Siberia in the Paleolithic period. Both the control and coding regions of their mitochondrial DNA (mtDNA) were analyzed in detail, and we confidently assigned 54 mtDNAs to relevant haplogroups. Haplogroups N9b, D4h2, G1b, and M7a were observed in these individuals, with N9b being the predominant one. The fact that all these haplogroups, except M7a, were observed with relatively high frequencies in the southeastern Siberians, but were absent in southeastern Asian populations, implies that most of the Hokkaido Jomon people were direct descendants of Paleolithic Siberians. The coalescence time of N9b (ca. 22,000 years) was before or during the last glacial maximum, implying that the initial trigger for the Jomon migration in Hokkaido was increased glaciations during this period. Interestingly, Hokkaido Jomons lack specific haplogroups that are prevailing in present-day native Siberians, implying that diffusion of these haplogroups in Siberia might have been after the beginning of the Jomon era, about 15,000 years before present.

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Bronze age Y-chromosomes and mtDNA from Liao River (northern China)

From the paper:

The dominant haplogroup in the Dadianzi people was D4 shared by
five individuals who were associated with four different haplotypes.
The other haplotype belonging to haplogroup D in the Dadianzi population
was designated as D5 by the mutation at site 16 189 (T to C).
The haplogroup M7c included two haplotypes, which were shared by two
individuals in ancient Dadianzi people. The other haplogroups, including
A4, F1b, G1a, M9a, M10 and M8z, were each present in one individual.

Seven male samples were chosen for Y chromosome SNPs among
the 14 individuals. Three samples (S1, S2 and S13) exhibited the
mutations M89C-T, M9C-G, M214T-C and M231G-A, which
were attributed to haplogroup N ( N1C). Two samples (S8 and S12)
exhibited the mutations: M89C-T, M9C-G, M175-5 bp del and
M122T-C, belonging to haplogroup O3 (M122). We failed to obtain
any product from two samples (S5 and S14) (Table 3).

Journal of Human Genetics advance online publication 22 September 2011; doi: 10.1038/jhg.2011.102

Genetic characteristics and migration history of a bronze culture population in the West Liao-River valley revealed by ancient DNA

Hongjie Li et al.

In order to study the genetic characteristics of the Lower Xiajiadian culture (LXC) population, a main bronze culture branch in northern China dated 4500–3500 years ago, two uniparentally inherited markers, mitochondrial DNA and Y-chromosome single-nucleotide polymorphisms (Y-SNPs), were analyzed on 14 human remains excavated from the Dadianzi site. The 14 sequences, which contained 13 haplotypes, were assigned to 9 haplogroups, and Y-SNP typing of 5 male individuals assigned them to haplogroups N (M231) and O3 (M122). The results indicate that the LXC population mainly included people carrying haplogroups from northern Asia who had lived in this region since the Neolithic period, as well as genetic evidence of immigration from the Central Plain. Later in the Bronze Age, part of the population migrated to the south away from a cooler climate, which ultimately influenced the gene pool in the Central Plain. Thus, climate change is an important factor, which drove the population migration during the Bronze Age in northern China. Based on these results, the local genetic continuity did not seem to be affected by outward migration, although more data are needed especially from other ancient populations to determine the influence of return migration on genetic continuity.

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