Scientists have, for the first time, successfully created a fine ‘genetic map’ of the Han Chinese, the largest ethnic population in the world, through a genome-wide DNA variation study. This ‘genetic map’ provides invaluable information on the population structure and evolutionary history of this group of people, and with that, helps to determine the design and interpretation of genetic studies of human diseases among them.
The study, led by Dr Liu Jianjun, Human Genetics Group Leader at the Genome Institute of Singapore (GIS), was published online on 25 November 2009 in the American Journal of Human Genetics. The GIS is a biomedical research institute of the Agency for Science, Technology and Research (A*STAR), Singapore.
Using genome-wide DNA variation information in over 6,000 Han Chinese samples from 10 provinces in China, the scientists were able to show that the northern inhabitants were genetically distinguishable from those in the south, which seems to be extremely consistent with the historical migration pattern of the Han Chinese. It also revealed that the genetic divergence was closely correlated with the geographic map of China. The close resemblance between the ‘genetic’ and geographic maps of the Han Chinese suggests the persistence of local co-ancestry in the country.
Dr Liu said, “The genome-wide genetic variation study is a powerful tool which may be used to infer a person’s ancestral origin and to study population relationships. For example, an ethnic Chinese born and bred in Singapore can still be traced back to his or her ancestral roots in China. By investigating the genome-wide DNA variation, we can determine whether an anonymous person is a Chinese, what the ancestral origin of this person in China may be, and sometimes which dialect group of the Han Chinese this person may belong to. More importantly, our study provides information for a better design of genetic studies in the search for genes that confer susceptibility to various diseases.”
Of particular interest to Singapore are the findings that while the majority of Singaporean Chinese hail from Southern China as expected, some have a more northern ancestral origin.
GIS Executive Director, Prof Edison Liu, said, “Genome association studies have provided significant insights into the genes involved in common disorders such as diabetes, high cholesterol, allergies, and neurological disorders, but most of this work has been done on Caucasian populations. More recently, Dr Liu Jianjun from our institute has been working with his Chinese colleagues to define the genetic causes of some of these diseases in Asian populations. This work refined those tools so that the results will not be obscured by subtle differences in the genetic diversity of Asian populations. In the process, Dr Liu has reconstructed a genetic historical map of the Chinese people as they migrated from south to north over evolutionary time. “
Prof Chia Kee Seng, Head, Department of Epidemiology & Public Health, NUS Director, NUS-GIS Centre for Molecular Epidemiology, also added, “There are definite differences in genetic architecture between populations. We have seen this in the Singapore Genome Variation Project, a Joint NUH-GIS effort. Understanding these differences is crucial in exploring how genes and environment interact to cause diseases.”
The finding is part of a larger ongoing project on the genome-wide association study of diseases among the Chinese population. The project is a collaboration between GIS and several institutions and universities in China. For example, Nature Genetics published, in January 2009, the findings of researchers at the GIS and Anhui Medical University, China, on psoriasis, a common chronic skin disease. In that study, led by Dr Liu Jianjun at the GIS and Dr Zhang Xuejun at the Anhui Medical University, the scientists discovered a genetic variant that is able to provide protection against the development of psoriasis. More recently, the collaboration made another breakthrough in the discovery of over a dozen genetic risk variants for systematic lupus erythematosus (SLE) in the Chinese population, which was published in Nature Genetics in October 2009. Work on other diseases is being geared for publication as well.
Notes to the Editor:
Research publication:
The research findings described in the press release can be found in the November 25, 2009 online issue of American Journal of Human Genetics under the title “Genetic Structure of the Han Chinese Population Revealed by Genome-wide SNP Variation”.
Authors:
Jieming Chen 1*, Houfeng Zheng 3,4,5*, Jin-Xin Bei 6,7, Liangdan Sun 3,4 5, Wei-hua Jia 6,7, Tao Li 8,9, Furen Zhang 10, Mark Seielstad 1,2,11, Yi-Xin Zeng 6,7, Xuejun Zhang 3,4 5, Jianjun Liu 1,2,3,4
1. Human Genetics, Genome Institute of Singapore, Singapore 138672, Singapore
2. Centre for Molecular Epidemiology, (Yong Loo Lin) School of Medicine, the National University of Singapore 117597, Singapore
3. Institute of Dermatology and Department of Dermatology at No.1 Hospital, Anhui Medical University
4. The Key Laboratory of Gene Resource Utilization for Severe Diseases, Ministry of Education and Anhui Province
5. Department of Dermatology and Venereology, Anhui Medical University, Hefei, Anhui 230032, China
6. State Key Laboratory of Oncology in Southern China, Guangzhou, China
7. Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, China
8. The Department of Psychiatry & Psychiatric laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
9. The Department of Psychological Medicine and Psychiatry, Institute of Psychiatry, King’s College London, London SE5 8AF, UK
10. Shandong Provincial Institute of Dermatology and Venereology, Shandong Academy of Medical Science, Jinan, Shandong, China
11. Dept. of Epidemiology, Harvard School of Public Health, Boston, Massachusetts 02115, USA
Correspondence: Dr Jianjun Liu, Genome Institute of Singapore
* These authors contributed equally to this manuscript.
About the Genome Institute of Singapore
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