Genetic variation is known to contribute to an individual’s susceptibility to disease and response to treatments. Populations from different parts of the world show significant genetic diversity that is a consequence of their population histories. Asian populations are not extensively studied, and their genetic make-up is poorly understood, hindering efforts to discover disease-associated genes that impact on the health of individuals from these populations.
Singapore, with its ethnically diverse population consisting of three major ethnic groups (Chinese, Malay and Indian), capture 80 percent of Asia’s diversity. Hence, Singapore investigators performed whole genome sequencing on close to 5,000 Singaporeans (2,780 Chinese, 903 Malays and 1,127 Indians) over two years to establish a genetic reference on the local population for subsequent studies.
The study revealed a noticeable degree of genetic intermingling among the three ethnic groups, of which Chinese and Malays are more closely related. It suggests that Malays split from Chinese about 24,800 years ago. The Malays then experienced significant gene inflow with East Asians about 1,700 years ago, coinciding with the Austronesian expansion, a hypothesized historical migration of peoples from Taiwan/East Asia to Southeast Asia and further to remote Pacific and Oceania islands.
In addition, the team identified 98.3 million genetic variants across the Singapore genomes. Of these, more than half have not been previously reported in public databases, which to date have focused on Western and European populations. It also identified 20 candidate loci for natural selection where genome sequences were altered as a result of survival and adaptation to local environments during human evolution.
14 loci were found to be associated with human traits and diseases. This may explain why certain diseases and human traits, such as ALDH2 deficiency, which is associated with Asian Flush, are more or less common in Asians. These results show the relevance and utility of performing genetic studies across diverse populations in Asia.
“The project provides a pilot genetic map of Asian populations that allows us to measure precisely the genetic contribution to disease, and combine it with other sources of data within a data-driven healthcare system,” said Professor Patrick Tan, executive director at the Genome Institute of Singapore, who is a senior author on the study.
“Potentially, this will provide insights to prevent disease before it occurs, diagnose disease earlier and ensure that therapies are deployed in a way that maximizes clinical benefits while minimizing adverse effects. This will benefit both Singapore and the Asian population at large by providing more effective and efficient healthcare services,” he added.
Originally published in Asian Scientist. Read original article here.