英国研究人员发现，使人类能够思考和推理的基因开始进化于5亿年前。从这一刻起，人类拥有了学习复杂技能、分析形势、灵活思考的能力。发表在《自然·神经科学》上的此项研究成果，同时也揭示出行为进化和脑部疾病起源之间的直接联系。
科学家们认为，为提高我们的心智能力做出贡献的相同基因，也要为某些脑部疾病的形成负上责任。该研究表明，人类智力的形成，是人类祖先大脑基因数量增长的结果。生活在5亿年前的一种简单无脊椎动物经历了一场“遗传事故”，导致形成了这些基因的额外副本。这种动物的后代受益于这些额外的基因，最终导致了包括人类在内的行为复杂的脊椎动物的出现。
该研究小组使用比较任务法研究了小鼠和人类的心智能力，具体涉及识别触摸屏电脑上的物体。然后，研究人员将这些行为测试的结果，与各种行为进化时不同物种的遗传密码信息结合起来。他们发现，更高的心智功能在人类和小鼠身上均受控于相同的基因。
研究还表明，当这些基因发生突变或损坏时，它们会削弱更高的心智功能。更高的智力和更复杂的行为导致了更多的精神疾病。（生物谷Bioon.com）
doi: 10.1038/nn.3276.
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Synaptic scaffold evolution generated components of vertebrate cognitive complexity
Nithianantharajah J, Komiyama NH, McKechanie A, Johnstone M, Blackwood DH, Clair DS, Emes RD, van de Lagemaat LN, Saksida LM, Bussey TJ, Grant SG.
The origins and evolution of higher cognitive functions, including complex forms of learning, attention and executive functions, are unknown. A potential mechanism driving the evolution of vertebrate cognition early in the vertebrate lineage (550 million years ago) was genome duplication and subsequent diversification of postsynaptic genes. Here we report, to our knowledge, the first genetic analysis of a vertebrate gene family in cognitive functions measured using computerized touchscreens. Comparison of mice carrying mutations in each of the four Dlg paralogs showed that simple associative learning required Dlg4, whereas Dlg2 and Dlg3 diversified to have opposing functions in complex cognitive processes. Exploiting the translational utility of touchscreens in humans and mice, testing Dlg2 mutations in both species showed that Dlg2's role in complex learning, cognitive flexibility and attention has been highly conserved over 100 million years. Dlg-family mutations underlie psychiatric disorders, suggesting that genome evolution expanded the complexity of vertebrate cognition at the cost of susceptibility to mental illness.
