中国人的基因中存在能够分解酒中毒素的基因，且这种基因仅存在于中、日、韩等东亚人群中间。复旦大学生命科学学院李辉课题组最近研究发现了东亚人拥有的这种特别的“杜康基因”，它对酒精有很强的解毒作用。最新一期的英国《人类遗传学年报》刊登了这项研究成果。
这种“杜康基因”实际上是乙醇脱氢酶基因的一种变体。因为这种基因的形成年代与“杜康酿酒”这一历史故事的时间相吻合，因此被专家戏称为“杜康基因”。在生物学中，乙醇脱氢酶基因可以降解因食物储存过久、发霉、变质产生的一些毒素。在世界上46种人群里，这种酶的变体非常多，差别也很大，一共分为7种类型。其中，第六、第七型在中国人里出现，后来传到日本、韩国。第七种类型具有特别强的解毒功能，而在汉族人群中，拥有这种基因的人占到70%以上。
研究人员通过古尸进行古DNA的比对分析后发现，在中国新石器时代，这种变体几乎看不见；到了秦汉时代，变体的比例就变得很高。研究结论认为，这个基因的变化过程在约2800年前的中国发生。考古学证据显示，饮酒从夏商时期开始流行，饮酒引起了中国人大范围优胜劣汰的过程，因为携带“杜康基因”的人能更快地降解大多与乙醇相关的毒素，从而减轻了酒精对人体的不利影响，使得汉族在遗传上具有一定优势，对汉族人口扩张起了重要作用。
东亚人群中有分解酒精能力特别强的乙醇脱氢酶ADH1B第七型基因，但这并不意味着东亚人可以放肆饮酒。李辉表示，这种特别的基因只能是将酒精分解为乙醛，乙醛还是对人体有毒性的，很多人喝酒脸红就是由于乙醛刺激。
生物探索推荐英文原文：
Diversification of the ADH1B during Expansion of Modern Humans
Summary
A variant allele, ADH1B*48His, also known as ADH1B*2, at the human Alcohol Dehydrogenase 1B gene (ADH1B) is strongly associated with alcoholism in some populations and has an unusual geographic distribution. Strong evidence implies selection has increased the frequency of this allele in some East Asian populations but does not fully explain its geographic pattern. We have studied haplotypes of 10 single nucleotide polymorphisms (SNPs) and two short tandem repeat polymorphisms (STRPs) in the ADH1B region in 2,206 individuals from a worldwide set of populations. These SNPs and STRPs define nine common haplogroups most of which have distinct geographic patterns. The haplogroups H5 and H6, both with the derived ADH1B*48His allele, appear restricted to the Middle East and East Asia, respectively. The positively selected H7 is derived from H6 by a new regulatory region variant defining SNP rs3811801 restricted to East Asia. Age estimates of the haplogroups based on the STRPs also agree with the time of the migration events estimated by other studies. H7 is estimated to have expanded recently, around 2,800 years ago, and ancient DNA samples from North China confirm its presence about that time. The dating of the H7 expansion may help understand the selective force on the ADH1B gene.
