Smaller Genetic Risk in Catabolic Process Explains Lower Energy Expenditure, More Athletic Capability and Higher Prevalence of Obesity in Africans

Lower energy expenditure (EE) for physical activity was observed in Africans than in Europeans, which might contribute to the higher prevalence of obesity and more athletic capability in Africans. But it is still unclear why EE is lower among African populations. In this study we tried to explore the genetic mechanism underlying lower EE in Africans. We screened 231 common variants with possibly harmful impact on 182 genes in the catabolic process. The genetic risk, including the total number of mutations and the sum of harmful probabilities, was calculated and analyzed for the screened variants at a population level. Results of the genetic risk among human groups showed that most Africans (3 out of 4 groups) had a significantly smaller genetic risk in the catabolic process than Europeans and Asians, which might result in higher efficiency of generating energy among Africans. In sport competitions, athletes need massive amounts of energy expenditure in a short period of time, so higher efficiency of energy generation might help make African-descendent athletes more powerful. On the other hand, higher efficiency of generating energy might also result in consuming smaller volumes of body mass. As a result, Africans might be more vulnerable to obesity compared to the other races when under the same or similar conditions. Therefore, the smaller genetic risk in the catabolic process might be at the core of understanding lower EE, more athletic capability and higher prevalence of obesity in Africans.

研究发现，非洲人群的体力活动能量消耗（energy expenditure, EE）低于欧洲人群，这或与非洲人群更高的肥胖患病率及更强的运动能力相关。但目前学界仍未明确非洲人群能量消耗更低的原因。本研究旨在探究非洲人群能量消耗更低的遗传机制。我们针对分解代谢过程（catabolic process）中的182个基因，筛选出231个可能对其产生有害影响的常见变异（common variants）。基于上述筛选出的变异，从突变总数与有害概率总和两个维度计算遗传风险（genetic risk），并在群体水平（population level）开展分析。人类族群的遗传风险分析结果显示，4个非洲族群中有3个的分解代谢过程遗传风险显著低于欧洲人群与亚洲人群，这或可提升非洲人群的能量产生效率。在体育赛事中，运动员需要在短时间内消耗大量能量，因此更高的能量产生效率或有助于非洲裔运动员展现更强的运动实力。另一方面，更高的能量产生效率也可能意味着机体仅需消耗更少的体质量。因此，在相同或相似的条件下，非洲人群相较于其他种族或许更易罹患肥胖。综上，分解代谢过程中较低的遗传风险，或为理解非洲人群能量消耗更低、运动能力更强且肥胖患病率更高的核心机制。