Researchers have found a distinctive human migratory dispersal pattern involving the mitochondrial DNA haplogroup M9a’b (associated with a Mesolithic culture) originating in Southern China, and/or Southeast Asia(North Vietnam), and dispersing into East Eurasia. Particularly significant for the question of origins of the Japanese here, was the haplogroup M9a1a1 that showed a distinct distribution pattern:
- Most of the M9a1a1 basal lineages were distributed in southern China, southwestern China, as well as, northern China, Japan and Korea
- Its major sub-haplogroup M9a1a1c was prevalent in northern China, Korea and Japan.
M9a1a1 is estimated to have emerged around 14 to 17 kya.
See extract below:
Min-Sheng Peng, et al., “Inland post-glacial dispersal in East Asia revealed by mitochondrial haplogroup M9a’b“, Journal: BMC Biology – BMC BIOL , vol. 9, no. 1, pp. 2-12, 2011 DOI: 10.1186/1741-7007-9-2 pdf doc.
BACKGROUND: Archaeological studies have revealed a series of cultural changes around the Last Glacial Maximum in East Asia; whether these changes left any signatures in the gene pool of East Asians remains poorly indicated. To achieve deeper insights into the demographic history of modern humans in East Asia around the Last Glacial Maximum, we extensively analyzed mitochondrial DNA haplogroup M9a’b, a specific haplogroup that was suggested to have some potential for tracing the migration around the Last Glacial Maximum in East Eurasia.
RESULTS: A total of 837 M9a’b mitochondrial DNAs (583 from the literature, while the remaining 254 were newly collected in this study) pinpointed from over 28,000 subjects residing across East Eurasia were studied here. Fifty-nine representative samples were further selected for total mitochondrial DNA sequencing so we could better understand the phylogeny within M9a’b. Based on the updated phylogeny, an extensive phylogeographic analysis was carried out to reveal the differentiation of haplogroup M9a’b and to reconstruct the dispersal histories.
CONCLUSIONS: Our results indicated that southern China and/or Southeast Asia likely served as the source of some post-Last Glacial Maximum dispersal(s). The detailed dissection of haplogroup M9a’b revealed the existence of an inland dispersal in mainland East Asia during the post-glacial period. It was this dispersal that expanded not only to western China but also to northeast India and the south Himalaya region. A similar phylogeographic distribution pattern was also observed for haplogroup F1c, thus substantiating our proposition. This inland post-glacial dispersal was in agreement with the spread of the Mesolithic culture originating in South China and northern Vietnam.
An East Eurasian specific mtDNA haplogroup M9a’b for four reasons:
1) M9a’b distributes widely in mainland East Asia  and is relatively concentrated in Tibet (approximately 19.2%) [15,16] and its surrounding regions, including Nepal (approximately 11.6%) , Sikkim (approximately 11.7%)  and northeast India (approximately 8.6%) [18,19].
2) The phylogeny of haplogroup M9a’b indicated that this clade might be involved in some northward migrations into East Asia from Southeast Asia. With the exception of M9a1, most basal branches of M9a were distributed in southern China (6/15) and Southeast Asia (7/15); this pattern suggested that M9a might have a southern origin. The distribution pattern of M9a1 was rather complex: although this haplogroup did bear some genetic imprints of southern origin by harboring a basal lineage (that is, HN-H H27) from southern China, its effect had actually extended to northern China and Japan (for example, M9a1a1a, M9a1a1b, and M9a1a1c1a), as well as, western China (that is, southwestern China, northwestern China, and Tibet), northeast India (including Bangladesh), and the south Himalaya region (for example, M9a1b1, M9a1a2, and M9a1a1c1b). Based on this pattern, it seemed that haplogroup M9a1 had most likely been involved in some northward and westward dispersal(s) in East Asia.
Phylogeographic distribution The updated phylogenetic tree of haplogroup M9a’b provided a basis for us to reanalyze the previously published data and to perform a well-defined phylogeographic analysis of this haplogroup. To better characterize the demographic history of M9a’b, the median-joining network was constructed based on all available M9a’b mtDNAs (Figure 3).
Our comprehensive study of haplogroup M9a’b substantiated the notion that the origin of this haplogroup was most likely located in southern China and/or mainland Southeast Asia. As displayed in Figure 3, most of the basal lineages within M9a (that is, M9a*; excluding M9a1a and M9a1b mtDNAs) came from southern China, southwestern China, and Southeast Asia, strongly suggesting a southern origin of M9a. This result received further support from M9b: 9 of the 11 M9b sequences were observed in southern China, southwestern China, and Southeast Asia, while the remaining two were found in northwestern China and northern China, respectively (Figure 3; see Additional file 1).
Similar to the observation from the phylogenetic tree of the complete mtDNAs (Figure 2), the median-network showed that the dominant clade (M9a1) within M9a presented a quite different geographic distribution pattern from its sister cluster M9a* (Figure 3).
…haplogroup M9a1b, the basal lineages were mainly restricted to western China and Myanmar, whereas M9a1b1 spread not only in western China and Myanmar, but also in northeast India and the south Himalaya region (Figure 3). The basal lineages belonging to M9a1a* were mainly found in southern China (Figure 3). One of its derivatives, haplogroup M9a1a2, displayed a restricted distribution in western China, Myanmar, northeast India, and the south Himalaya region (Figure 3 and 4; see Additional file 2), and presented a similar pattern to that of haplogroup M9a1b1. Nevertheless, haplogroup M9a1a1 showed a distinct distribution pattern: most of the M9a1a1 basal lineages were distributed in southern China, southwestern China, as well as, northern China, Japan and Korea, whereas its major sub-haplogroup M9a1a1c was prevalent in northern China, Korea, and Japan (Figure 3 and 4; see Additional file 2). Remarkably, the M9a1a1 lineages found in Tibet were almost clustered into haplogroup M9a1a1c1b …
The whole haplogroup M9a’b showed a coalescence time of approximately 26 to 28 kya. The estimated coalescence age of haplogroup M9a was approximately 18 to 23 kya.
Within haplogroup M9a1, haplogroups M9a1a1 and M9a1b1 emerged around 14 to 17 kya and 9 to 12 kya, respectively. For haplogroup M9a1a2, because of the small number of available mtDNA genome sequences,which would bias the age estimates, we adopted the age estimation result based on HVS-I data (11.3 ± 3.5 kya).
As a result, nearly all the age estimates placed the origin of haplogroup M9a1a1 in the Late Glacial episode,whereas haplogroups M9a1b1 and M9a1a2 are in a more recent post-glacial period (the end of the Pleistocene and the early Holocene), despite a fact that these ages should be received with caution …