Genetic Diversity in Han Chinese

November 30, 2009 · Posted in Research

by HUGO Matters Editor Hsien-Hsien Lei, PhD

When I was in high school, a classmate of mine commented on the San Francisco Miss Chinatown competition.

“How can they tell the difference between all the girls?”

Perhaps I should send her a copy of two recent papers published in the American Journal of Human Genetics (AJHG) that found significant genetic and genomic diversity within the Han Chinese population.

The first paper by Jieming Chen et al. from the Genome Institute of Singapore sampled Chinese from ten provinces in addition to Beijing, Shanghai, and Singapore. They examined over 350,000 genome-wide autosomal SNPs and developed a genetic map of the Han Chinese. They found that:

Within Guangdong province, genetic differentiation correlated with language.
Genetic patterns correlated with north to south geographic orientations but not east to west. This finding is consistent with historical migration patterns.
Metropolitan cities in China have experienced strong modern migration and are thus more difficult to tease apart genetically.
Han Chinese individuals in Singapore are closest genetically with individuals from southern China.
Spurious associations in genome-wide association studies (GWAS) can occur if population stratification in Chinese populations is not addressed. Geographic matching, however, can serve as a proxy for genetic matching.

"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," senior author Liu Jianjun, leader of the GIS Human Genetics Group, said in a statement. "More importantly, our study provides information for a better design of genetic studies in the search for genes that confer susceptibility to various diseases."

Research Teams Map Genetic, Genomic Patterns in Han Chinese Population | GenomeWeb Daily News | Arrays | GenomeWeb

A second smaller study also published in in AJHG by Xu Shuhua et al., confirmed the observations of the paper above. The researchers concluded that genetic differentiation between northern, central, and southern Han can lead to false-positive results in association studies.

NB: On a related note, these maps of China are a riot. They were created by people around China and depict their views of the various provinces.