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Scientists have identified three genes that may have played an important part in a major development in human evolution.科学家已经确定了三个可能在人类进化的重大发展中起重要作用的基因。

The genes are being linked to the increase in brain size that took place in ancestors of human beings. This increase led to the development of mental abilities that define what it means to be human.这些基因与人类祖先发生的大脑大小的增加有关。 这种增长导致了定义人类含义的心理能力的发展。

Researchers published two reports on their observations of the genes in the publication Cell in late May.研究人员发表了两份有关他们对5月下旬出版物细胞基因的观察的报告。

The researchers believe the genes first appeared between three and four million years ago. This was just before a period in the fossil record that shows a major brain enlargement in the species from which humans evolved.研究人员认为，这些基因首次出现在三到四百万年前。 这是在化石记录中的一段时间之前，显示了人类进化的物种中的大脑肿大。

The three genes share almost the exact same qualities. Along with a fourth one that seems to serve no purpose, they are called NOTCH2NL genes. They came from a gene family believed to have developed hundreds of millions of years ago. They are also important in the development of embryos.这三个基因几乎具有完全相同的品质。 除了似乎没有目的的第四个外，它们被称为Notch2nl基因。 他们来自一个据信基因家族，该家族已经发展了数亿年。 它们在胚胎的发展中也很重要。

The NOTCH2NL genes are especially active in the collection of nerve stem cells in the cerebral cortex. The cerebral cortex is the outer part of the brain responsible for the highest mental processes. These include language, memory and reasoning.Notch2nl基因在大脑皮层中神经干细胞的收集中特别活跃。 大脑皮层是负责最高心理过程的大脑外部部分。 这些包括语言，记忆和推理。

The genes were found to slow the development of stem cells in the cerebral cortex into neurons in the embryo. The researchers say this delay leads to the production of a higher number of more developed nerve cells in this area of the brain.发现这些基因会减慢脑皮质中干细胞在胚胎中神经元中的发育。 研究人员说，这种延迟会导致在大脑该区域中产生更高数量的发达神经细胞。

Pierre Vanderhaeghen is a developmental neurobiologist at the Université Libre de Bruxelles in Belgium. He told the Reuters news service that, in large part, the cerebral cortex is responsible for what defines humans as a species and as individuals.Pierre Vanderhaeghen是比利时的Libre de Bruxelles大学的发展神经生物学家。 他告诉路透社新闻服务，在很大程度上，大脑皮层造成了将人类定义为一种物种和个人的原因。

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