Scientists in China have identified a specific gene that may increase resistance to obesity, potentially unraveling the complex mechanisms behind this global health issue.

"Mitochondria are often referred to as the cell’s powerhouses, generating 80 to 90 percent of the energy needed for various human behaviors. Mitochondrial function has long been associated with obesity," Jin wrote.

Mitochondrial DNA is inherited only from the mother and is more susceptible to genetic mutations than nuclear DNA, which is acquired from both parents. DNA in mitochondria is often inherited exclusively from the mother, unlike DNA in the cell nucleus, which is acquired from both parents. It is more prone to accrue genetic mutations—which are frequently employed in evolutionary analyses—than nuclear DNA.

Mitochondria
Image Source: National Institutes of Health (NIH)

Although dietary habits and developmental stages are undoubtedly significant, a recent study conducted by Fudan University's Professor Jin Li and Associate Professor Zheng Hongxiang raises the possibility that genetics may also play a role. A form of mitochondrial DNA that is common in Southeast Asia and southern China has been found to offer protection against obesity. 2,877 samples from three separate populations in Guangxi, Jiangsu, and Henan were examined by the study. The peer-reviewed Journal of Genetics and Genomics published their findings.

The Genetic Connection to Obesity: Focusing on Mitochondria

Although nutrition and lifestyle choices are important, a new study from Fudan University headed by Professor Jin Li and Associate Professor Zheng Hongxiang makes several important observations about the role of genetics in determining the intensity of obesity.

Jin and his associates conducted association studies on sixteen basic mitochondrial DNA haplogroups, which are genetic lineages deriving from a single common ancestor. They found that there was a continuous correlation between a lower risk of obesity and a particular variation group, M7.
Subsequent investigation revealed that the M7b1a1 subgroup was most likely the source.

According to research conducted in 2019 and published in Molecular Biology and Evolution, Professor Kong Qingpeng of the Chinese Academy of Sciences discovered that this particular subgroup "was mainly distributed in southern China and mainland Southeast Asia and exhibited considerable frequencies in southern Han Chinese individuals – about 5 to 14 percent."

Jin suggested that the reason M7b1a1 lowers the risk of obesity might be due to a decrease in mitochondrial activity. "Decreased mitochondrial functions represent less energy conservation and more heat production, which could result in less weight gain," he wrote.

Jin said this further supports their hypothesis, adding: “M7b1a1 carriers with greater heat generation may have adapted to the cold climate in the Ice Age well, which may have been evolutionarily advantageous for positive natural selection.

"Our findings offer new insights into the genetic basis of obesity-related traits, enhancing our understanding of how genetics can influence body fat distribution and obesity risk," Jin concluded.

China's rate of poverty remains among the lowest globally, even with its fast economic growth. In terms of the prevalence of obesity worldwide, Chinese women were placed 190th and Chinese men 149th in a 2022 research that was published in The Lancet. Numerous additional grave medical disorders, such as type 2 diabetes and cardiovascular illnesses, are associated with obesity. Our awareness of obesity and its consequences is growing as medical science advances.

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