Y-chromosome Genotyping and Genetic Structure of Zhuang Populations

Department of Pathophysiology, Guangxi Medical University, Nanning 530021, China.
Acta Genetica Sinica 01/2007; 33(12):1060-72. DOI: 10.1016/S0379-4172(06)60143-1
Source: PubMed

ABSTRACT Zhuang, the largest ethnic minority population in China, is one of the descendant groups of the ancient Bai-Yue. Linguistically, Zhuang languages are grouped into northern and southern dialects. To characterize its genetic structure, 13 East Asian-specific Y-chromosome biallelic markers and 7 Y-chromosome short tandem repeat (STR) markers were used to infer the haplogroups of Zhuang populations. Our results showed that O*, O2a, and O1 are the predominant haplogroups in Zhuang. Frequency distribution and principal component analysis showed that Zhuang was closely related to groups of Bai-Yue origin and therefore was likely to be the descendant of Bai-Yue. The results of principal component analysis and hierarchical clustering analysis contradicted the linguistically derived north-south division. Interestingly, a west-east clinal trend of haplotype frequency changes was observed, which was supported by AMOVA analysis that showed that between-population variance of east-west division was larger than that of north-south division. O* network suggested that the Hongshuihe branch was the center of Zhuang. Our study suggests that there are three major components in Zhuang. The O* and O2a constituted the original component; later, O1 was brought into Zhuang, especially eastern Zhuang; and finally, northern Han population brought O3 into the Zhuang populations.

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Available from: Hui Li, Feb 12, 2014
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    • "In Fig. 4, networks of O2a*, O3*, and O3a5a were analyzed using six STRPs. The STRP haplotypes of the Pinghua samples (Electronic Supplementary Material, Table 1) were compared with those of the Han, Daic, and Hmong-Mien (Chen et al. 2006; Feng 2007; Li 2005; Li 2007). There are at least two central haplotypes in the network of O2a*: one in the upper portion, and one towards the center. "
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    ABSTRACT: The Han Chinese is the largest single ethnic group in the world, consisting of ten Chinese branches. With the exception of the Pinghua branch, the genetic structure of this group has been studied extensively, and Y chromosome and mitochondrial (mt)DNA data have demonstrated a coherent genetic structure of all Han Chinese. It is therefore believed that the Pinghua branch, being members of an old branch of the Han Chinese, despite being scattered in and around Guangxi Province where members of the Daic and Hmong-Mien are more prevalent than Han Chinese, is no exception. We have studied 470 individual samples (including 195 males) from Pinghua populations and other ethnic groups (Zhuang, Kam, Mulam, Laka, and Mien) from six areas (Hezhou, Fuchuan, Luocheng, Jinxiu, Sanjiang, and Wuxuan) in the north of the Guangxi Zhuang Autonomous Region of China. Both mtDNA and the Y chromosomes were typed in these samples. High frequencies of the Y chromosome haplogroups O2a* and O*, which always present at a high frequency among the populations of the southern minorities, were found in Pinghua populations. Only Pinghua populations in Luocheng and Jinxiu maintain the Han frequent haplogroup O3a5a. mtDNA lineages B4a, B5a, M*, F1a, M7b1, and N* were found in Pinghua populations, exhibiting a pattern similar to the neighboring indigenous populations, especially the Daic populations. Cluster analyses (dendrograms, principal component analyses, and networks) of Pinghua populations, the other Han branches, and other ethnic groups in East Asia indicated that Pinghua populations are much closer to the southern minorities than to the other Han branches. Admixture analyses confirmed this result. In conclusion, we argue that Pinghua populations did not descend from Han Chinese, but from southern minorities. The ancestral populations of Pinghua people were assimilated by the Han Chinese in terms of language, culture, and self-identification and, consequently, the Pinghua people became an exceptional branch of Han Chinese's coherent genetic structure.
    Journal of Human Genetics 02/2008; 53(4):303-13. DOI:10.1007/s10038-008-0250-x · 2.53 Impact Factor
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    ABSTRACT: The recent paper by Shi et al. (2008) provided the most details for the ethnic features of Y chromosome haplogroup D. The geographic distribution and age estimate for haplogroup D and its sub-clades helps in understanding the origin and migration processes of the early modern human in East Asia. Clades DE* and D* were found in Tibetan and Thai respectively. These findings make the search of the birth place of haplogroup D possible. Here we continued the discussion of Chandrasekar et al. (2007). The frequencies of haplogroup D in various populations of East Asia were collected from all the available literature. The analyses showed that the emergence of haplogroup D may be between India and Indochina. Clade D1 emerged subsequently when population move to the east. After clade D* diffused to the whole East Asia, it gave birth to clade D2 in Japan and clade D3 in Tibet independently.
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    ABSTRACT: The Y chromosome evolves from an autochromosome and accumulates male-related genes including sex-determining region of Y-chromosome (SRY) and several spermatogenesis-related genes. The human Y chromosome (60 Mb long) is largely composed of repetitive sequences that give it a heterochromatic appearance, and it consists of pseudoautosomal, euchromatic, and heterochromatic regions. Located on the two extremities of the Y chromosome, pseudoautosomal regions 1 and 2 (PAR1 and PAR2, 2.6 Mb and 320 bp long, respectively) are homologs with the termini of the X chromosome. The euchromatic region and some of the repeat-rich heterochromatic parts of the Y chromosome are called "male-specific Y" (MSY), which occupy more than 95% of the whole Y chromosome. After evolution, the Y chromosome becomes the smallest in size with the least number of genes but with the most number of copies of genes that are mostly spermatogenesis-related. The Y chromosome is characterized by highly repetitive sequences (including direct repeats, inverted repeats, and palindromes) and high polymorphism. Several gene rearrangements on the Y chromosome occur during evolution owing to its specific gene structure. The consequences of such rearrangements are not only loss but also gain of specific genes. One hundred and fifty three haplotypes have been discovered in the human Y chromosome. The structure of the Y chromosome in the GenBank belongs to haplotype R1. There are 220 genes (104 coding genes, 111 pseudogenes, and 5 other uncategorized genes) according to the most recent count. The 104 coding genes encode a total of about 48 proteins/protein families (including putative proteins/protein families). Among them, 16 gene products have been discovered in the azoospermia factor region (AZF) and are related to spermatogenesis. It has been discovered that one subset of gene rearrangements on the Y chromosome, "micro-deletions", is a major cause of male infertility in some populations. However, controversies exist about different Y chromosome haplotypes. Six AZFs of the Y chromosome have been discovered including AZFa, AZFb, AZFc, and their combinations AZFbc, AZFabc, and partial AZFc called AZFc/gr/gr. Different deletions in AZF lead to different content spermatogenesis loss from teratozoospermia to infertility in different populations depending on their Y haplotypes. This article describes the structure of the human Y chromosome and investigates the causes of micro-deletions and their relationship with male infertility from the view of chromosome evolution. After analysis of the relationship between AZFc and male infertility, we concluded that spermatogenesis is controlled by a network of genes, which may locate on the Y chromosome, the autochromosomes, or even on the X chromosome. Further investigation of the molecular mechanisms underlying male fertility/infertility will facilitate our knowledge of functional genomics.
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