Date of Award

1-1-2005

Degree Type

Thesis

Degree Name

Doctor of Philosophy

Faculty

Faculty of Computing, Health and Science

First Advisor

Professor Alan Bittles

Abstract

During the course of the last decade, genetic data have increasingly complemented linguistic, archaeological and palaeontological evidence in efforts to reconstruct human history. As technology has developed, studies have utilised genomic techniques in tracing the origins and migratory patterns of modem humans. East Asia is a particular hotspot of human migration, _especially Mainland China where a large number of human fossils have been unearthed and more than 20% of the wor1d's population now resides. There are 56 officially recognised ethnic groups (minzu) within the population of PR China which totals 1,300 million. The majority Han population is distributed throughout the country and forms 90% of the total, whereas the other 55 minority populations mostly live in peripheral and boundary regions. To date, information on these minorities has been fragmentary and, from both evolutionary and historical perspectives, data on their genetic profiles would be of considerable value in identifying their founding populations and genetic inter-relationships. There are also strongly conflicting opinions on the origins of the Han and the degree to which they can be regarded as genetically homogenous. The current study measured the genetic diversity and ancestry of nine ethnic populations resident in PR China. In addition to the Han, these study populations comprised the Miao, Yao, Kucong and Tibetan communities from Yunnan province in the southwest of the country, and four Muslim populations, the Hui, Bo'an, Dongxiang and Sala from northern and central China. Both biparental and uniparental genetic influences on the populations were examined by the analysis of autosomal, mitochondrial and Y -chromosome markers. In general, it was found that the study populations displayed diverse paternal ancestries but more restricted maternal ancestries. From the Y-chromosome data in particular, major events such as the Neolithic population expansion and more recent historical events, such-as migration along the Silk Road, could be inferred. Through the use of autosomal markers, aspects of the internal structure of the study populations were uncovered, such as endogamy and/or consanguinity. These conclusions were made possible, in part, by experimental Likelihood-based stochastic coalescent modelling. Intriguingly. it was revealed that the Kucong of Yunnan, an ethnic group not previously surveyed for genetic diversity and not accorded official minority status within PR China. could possibly be representative of indigenous populations dating from the first migrations into East Asia. While other' more recent events could be inferred from summary statistics and phylogenetic and coalescent-based genetic analyses of the study populations, the changing definition of the ethnic study populations themselves proved to be the most important factor. It is therefore recommended that future studies primarily utilize a community-by-community approach, and not rely on the official minzu category as an accurate indicator of genetic ancestry.

Included in

Life Sciences Commons

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