英国爱丁堡大学的科学家研究发现，人类智力水平仅有一半取决于遗传因素，人类的思考能力是由一连串相关联的基因，而不是某一个单独的“聪明基因”决定的。该研究成果发表在2011年10月号的《Molecular Psychiatry》上。
上个世纪，大多数遗传学研究都断定人类智力至少有75%是取决于基因因素。
然而该项研究在分析了数千名成年人的案例后发现，75%这一比例或许并不准确。研究对3511名成年人进行了共计550，000份的单核苷酸多态性研究。人类基因组计划研究显示，单核苷酸多态性是人类DNA序列的单个碱基的变异，并导致了90%以上的人类基因突变。同时，该研究还对比了受访者另外两项技能——问题解决能力和知识水平，研究人员最终断定，人类之间智力水平的差异仅有4成到5成与基因相关。
这迫使人们开始严肃地思考这个问题：教育机会与其他环境因素，例如家庭背景和教师水平，在人类智力成长过程中究竟扮演了何等角色？
“我的团队所做的工作旨在发现到底什么因素决定了人们的智力水平。”研究者Deary说，“基因差异是人类智力可塑性差异的一个原因。”虽然该项研究显示出基因与智力水平之间的某些关联，但正如Deary所说的，这种影响并不总是“完全可靠、一锤定音”的。
Genome-wide association studies establish that human intelligence is highly heritable and polygenic
G Davies, A Tenesa, A Payton, J Yang, I J Deary
General intelligence is an important human quantitative trait that accounts for much of the variation in diverse cognitive abilities. Individual differences in intelligence are strongly associated with many important life outcomes, including educational and occupational attainments, income, health and lifespan. Data from twin and family studies are consistent with a high heritability of intelligence, but this inference has been controversial. We conducted a genome-wide analysis of 3511 unrelated adults with data on 549 692 single nucleotide polymorphisms (SNPs) and detailed phenotypes on cognitive traits. We estimate that 40% of the variation in crystallized-type intelligence and 51% of the variation in fluid-type intelligence between individuals is accounted for by linkage disequilibrium between genotyped common SNP markers and unknown causal variants. These estimates provide lower bounds for the narrow-sense heritability of the traits. We partitioned genetic variation on individual chromosomes and found that, on average, longer chromosomes explain more variation. Finally, using just SNP data we predicted ~1% of the variance of crystallized and fluid cognitive phenotypes in an independent sample (P=0.009 and 0.028, respectively). Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence.
文献链接：https://www.nature.com/mp/journal/v16/n10/full/mp201185a.html
