Two large scientific studies have found seven new genetic variants that make people put on weight, to add to two genes that were already linked to obesity in the general population.

    Both research teams – one led by deCode Genetics, an Icelandic biotechnology company, and the other an international academic consortium – published their findings on the 14 Dec in the journal Nature Genetics.

    The discoveries will be important for the global fight against obesity, one of the greatest public health problems of the 21st century.

    The most significant feature of the newly identified genes is that almost all of them are active in the brain, implying that they affect appetite rather than the biochemical processes of energy or fat metabolism.

    “This suggests that, as we work to develop better means of combating obesity, including using these discoveries as the first step in developing new drugs, we need to focus on the regulation of appetite at least as much as on the metabolic factors of how the body uses and stores energy,” said Kari Stefansson, chief executive of deCode.

    Samples from a total of more than 100,000 people were analysed in the two “genome-wide association studies”, which used the latest DNA-reading technology to associate genetic variations with body mass index.

    Body mass index is the most commonly used measure of obesity.

    Family and twin studies have shown that genetic factors account for 40-70 per cent of population variation in body mass index.

    Yet the first gene contributing to obesity in the general population, as opposed to people with rare metabolic disorders, was not discovered until 2007.

    Each of the newly identified genetic variations has only a modest effect: someone who carries all seven would typically be 1.5kg to 2kg heavier than an average adult.

    除了已经与普通人群肥胖症挂钩的两种基因，两项大型科学研究新发现了七种致人体重增加的基因变异。

    两个研究小组——一个由冰岛生物技术公司基因解码(deCode Genetics)领导，另一个为国际学者联盟——都于12月14日在《自然-遗传学》杂志(Nature Genetics)上公布了他们的发现。

    这些发现将对全球抵御肥胖症的战斗具有重要意义。肥胖症是21世纪最严重的公共健康问题之一。

    新发现的基因最显著的特征是，它们几乎全部活跃于大脑，这意味着它们影响着食欲，而非能量或脂肪新陈代谢的生化过程。

    基因解码公司首席执行官凯里•斯蒂芬森(Kari Stefansson)表示：“这表明，在我们努力改进抵御肥胖症的方法时，包括将这些发现作为研发新药物的第一步，我们对调整食欲的关注度，至少要达到对人体消耗和储存能量的新陈代谢因子的关注程度。”

    两项“全基因组关联研究”(genome-wide association studies)对来自10余万人的样本进行了分析，利用最新的DNA解读技术，将基因突变与人体质量指数(body mass index)联系起来。

    人体质量指数是采用最为广泛的肥胖测量标准。

    对家庭和双生子的研究表明，基因因素占人体质量指数群体变异的40%至70%。

    不过，导致普通人群肥胖（相对于罕见的新陈代谢紊乱人群）的基因直到2007年才被首次发现。

    每种新发现的基因突变都仅产生微弱的影响：携带全部七种基因的人通常会比普通成年人重1.5至2公斤。