4 genes that shape a Han Chinese face are identified in Shanghai study

Stephen Chen
·3-min read

Four genes shape the face of a Han Chinese person, according to a new study by a research team in Shanghai. Changes in these genes could make a chin narrower, eyebrows higher, nose longer and cheeks slimmer, or the opposite effect.

“We intend to fill a knowledge gap” concerning Chinese ethnicity on how genes help shape human faces, Professor Stefan Gruenewald, a lead author of the study with the Shanghai Institute of Nutrition and Health, said on Tuesday. “I will be upset if the knowledge is used for some wrong purposes,” he added.

A peer-reviewed paper about the discovery was published in the Journal of Genetics and Genomics on Monday.

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Because the face is highly heritable, the legitimacy of a newborn is often, and sometimes wrongly, judged by resemblance to its parents. But it was not until 2012 that scientists established a definite link between face and genes.

With potential applications in various sectors – such as generating a sketch of a criminal suspect from a drop of blood – a number of studies have been carried out on European, Latino, African and some Asian populations, but the facial genes for ethnic Han, who make up most of the population in China, had previously remained unknown.

The Shanghai team recruited more than 2,000 volunteers and took three-dimensional images of their faces. Each image was split into more than 32,000 segments, and blood samples were collected from the volunteers for genome sequencing. Researchers analysed the data to find genetic variants associated with tiny changes in facial features.

“I expected an easy job,” said Gruenewald, a mathematician. But it turned out that the sample was not as big as desired, some popular tools for computer analysis had limits when applied in this new field of research, and many promising gene candidates fell just below the threshold of statistical significance.

Four genes were identified, all important to face formation, the study suggested. The eyes, nose, chin and cheeks determined the unique look of a face, playing important roles in identification and communication.

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Forensic scientists have longed for a technology that would enable them to make a portrait of a suspect from DNA collected at a crime scene. Archaeologists want to use the trace genes preserved in bones to reconstruct the soft tissue of ancient human beings, such as the nose. Some doctors need tools to quickly screen a patient for gene-related diseases by looking at their face.

These potential applications are “something we have been looking at … [but] there is a boundary between knowledge-seeking and experimental techniques,” Gruenewald said.

Professor Wang Sijia, a co-author of the study, agreed. Facial reconstruction with DNA data was “still preliminary. The resolution is too low [for practical use],” Wang said.

One limitation of the study was that all of the volunteers came from the eastern Chinese city of Taizhou, possibly resulting in an underestimation of the genetic diversity in the Han population. “We have launched a new study with a much larger sample size,” he said.

According to the study, Han Chinese share one face-shaping gene with some people native to South America, while the other three genes are not found in other ethnic groups.

Genetic screening has already been used in many countries to reduce the risk of birth defects. In China, would-be parents are encouraged to opt for an abortion if a fetus carries a high-risk gene.

Whether such technology should be used to select children with traits such as superior intelligence, physical strength or beauty remains a matter of heated debate.

“Selection is a dangerous idea … [that] I oppose,” Gruenewald said.

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