Largest Ever Genetic Study on Chinese Women Reveals Human Traits
Chinese, American scientists have sequenced and analyzed a portion of genomes of over 140,000 pregnant women in China, the largest-scale genetic analysis of Chinese people to date, revealing associations between genes and birth outcomes, including the birth of twins and a woman’s age at first pregnancy. The study published on Thursday in the journal Cell also allowed researchers to reconstruct the intermarriage of different ethnic groups in China, and promised to help identify genes that make people susceptible to infectious diseases.
Researchers from BGI-Shenzhen used data from non-invasive prenatal testing (NIPT) to sequence randomly 6 to 10 per cent of each mother’s genome. “Although non-invasive prenatal testing is low-pass sequencing,” said the study’s co-senior author Xu Xun from BIG-Shenzhen, a genome sequencing centre in China. “There’s still a chance that using this data with a large population size will help us to have a much broader vision of what the Chinese genetic population looks like.” NIPT, a test that sequences small amounts of a mother’s cell-free DNA to screen for fetal trisomy, has been growing in popularity in China. It has been administered to approximately 6 to 7 million Chinese women.
They found that the variation in a gene called NRG1 was linked to a greater or lesser incidence of twins. One variant of the gene is more common in mothers with twins and is associated with hyperthyroidism.
A variant of another gene, EMB, was associated with older firsttime mothers, according to the study.
Also, the DNA sequencing in maternal blood revealed links between viruses and genes that determine susceptibility to disease. A variation in one gene was associated with a higher concentration of herpesvirus 6 in a mother’s blood.
Herpesvirus 6 is the most common cause of the relatively benign baby rash called roseola, but a high “viral load” correlates with more severe symptoms.
People with Alzheimer’s disease also have higher levels of herpesvirus 6 in their brains.
The study looked at 141,431 participants including 36 of China’s 55 ethnic minority groups.