Why East Asians larger brains? Chinese scientists to explain brain | | _ East Asia News

[Compilation/Wang Jialu observers network] Asians smarter than the other parts of the population? Asian greater brain capacity? According to the South China Morning Post, January 28, a latest research by Chinese scientists, solves the problems that plagued scientists for decades.

In China, a new study shows that East Asian populations in natural evolution, mutations tend to make the brain became larger as a result and did not find this phenomenon in Europe or Africa.

Results of this study, to solve a controversial scientists for decades provided a clue: why Asian people's brains bigger than European and African?

> Data

More than 30 years ago, United States scientists carried out a study on the capacity of the world's largest brain. Through the global survey of 20,000 of the modern human skull, scientists found that East Asians average cranial cavity volume of 1415 CC, while Europeans to 1362, Africans to 1268.

A series of subsequent studies have confirmed the results. In the last year of a magnetic resonance imaging study, scientists found that East Asians Transcranial higher, this allows the head to accommodate larger brains.

Researchers have proposed a series of hypotheses to explain this difference. Some say, living in a cold place for a long time may help to promote the development of the brain. Because in this kind of environment, larger more easily in its core parts of the brain to maintain a constant temperature, thinking and most of the activities were carried out in this area.

However, the climate that it is difficult to fully explain the people who live in the same latitude – such as the Chinese and Europeans have different brains.

Chinese researchers said a gene called CASC5--8 a brain volume 1 in the regulation of gene-perhaps would provide more clues. And most other similarly affected monkeys and early human brain size genes, homo sapiens CASC5 mutations took place relatively late, it occurred after our ancestors left Africa 50,000 to 100,000 years.

> Brain scans

Kunming Institute of Zoology of the Chinese Academy of Sciences researcher, soldiers under the leadership of Professor, the different populations of the CASC5 mutation was compared for the first time.

Study finds that brain regulatory gene CASC5 in the origins of modern process has accumulated 8 amino acid mutations, these mutations in non-human primates and humans (Neanderthals and dannisuowaren) does not exist, the modern sites of unique variations. Among them, 2 mutations in people has been fixed, while the other 6 are polymorphic loci in the crowd.

More interesting is that the 4 polymorphisms in this gene loci with high frequency in the population in East Asia, which includes China, Japan, and Mongolia East Asian people, closely related to the increase of the capacity of the human brain, and in European and African populations, 4 frequencies of polymorphic loci was low.

"In race angle, we of research results displayed, CASC5 in East crowd of mutation select has more big of gray matter capacity" (observation who network Note: "gray matter" is constitute cortex of main components, by neurons cell of cell body gathered and into), research personnel in human genetics magazine published of papers said, "instead, in European and African crowd in the does not found this a select signal".

"But why this phenomenon occurs is not yet fully clear now," they added.

In addition to the weather, other external factors could also make this choice, including social structures and cultural preferences, soldiers said, but these theories are still speculation phase, "accurate answer requires further study."

> Bed and breakfasts

Soldiers said the investigation did not show that Asians are smarter than other people. "Scientific research has failed to find any evidence to support the intellectual differences between the races. ”

However, he said, scientists generally agree that humans for acquiring larger brains and made the ultimate sacrifice.

It is learned that the brain takes a lot of energy, larger brains and made growth more difficult, and consume the resources of other parts of the body, which creates a lot of problems such as physical decline. Europeans generally are more stronger and bigger than Asian, soldiers said, but the difference in size is related to brain size, which requires further study.

"Darwinian selection theory may still apply today, but I believe that brain differences between races, will eventually disappear because of gene exchange in the world" (Observer Network Note: the Darwinian selection theory of survival of the fittest, ill be eliminated)

Another anthropologist, said in Beijing, this solved an important in human evolutionary history, but sensitive issues. "The results of these studies may lead to racism controversy", the unnamed anthropologists said.

Research data shows that the gene mutation in South Asia also showed a trend of higher frequency in the population, the anthropologist said, surveys will be very interesting to them. If they also conforms to the daerwenzheng theory of the brain, brain became larger, so this may mean that moved farther away from the African people, their brain development is even greater.

>: Tang Zheng Hanxing

Article keywords:
Brains of East Asia

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为什么东亚人大脑更大？中国科学家给出解释|大脑|东亚_新闻资讯

　　[编译/ 观察者网 王佳璐]亚洲人要比其他地区的人群更聪明？亚洲人的脑容量更大？据南华早报网1月28日报道，中国科学家的一项最新研究，解决了这一困扰科学家数十年的问题。

　　中国的一项最新研究表明，东亚人群在自然演化中，基因突变更偏向于使脑部变得更大这一结果，而在欧洲或者非洲并未发现这一现象。

　　这一研究结果，为解决困扰科学家们数十年的一个争议性问题提供了线索：为什么亚洲人的大脑比欧洲人和非洲的更大？

>资料图

　　30多年前，美国科学家进行了一场全球最大的针对脑部容量的研究。通过对全球2万具现代人头骨展开的调查，科学家们发现，东亚人的颅腔容积平均为1415立方厘米，而欧洲人为1362，非洲人为1268。

　　随后的一系列研究也证实了这一结果。在去年的一个核磁共振成像研究中，科学家们发现东亚人的颅顶更高，这让他们的头部能够容纳体积更大的大脑。

　　研究人员提出了一系列假设来解释这样的差异。一些人表示，长期在寒冷的地方居住可能有助于促进脑部的发育。因为在这样的环境中，体积较大的大脑更容易在其核心部位维持恒定温度，而绝大部分的思考活动是在这个部位进行的。

　　然而，气候说却难以充分解释在同一纬度生活的人——例如中国人和欧洲人，拥有不同脑容量的现象。

　　中国研究人员称，一种名为CASC5的基因——8个脑容量调控基因中的1个——可能为人们提供更多线索。和其他大部分同样影响猴子和早期人类脑部大小的基因不同，智人CASC5的基因突变发生较晚，它发生在我们祖先离开非洲大陆后的5万到10万年间。

>脑部扫描图

　　中国科学院昆明动物研究所的研究员，在宿兵教授的带领下，对不同人群的CASC5突变位点进行了首次对比。

　　研究发现，脑容量调控基因CASC5在现代人的起源过程中积累了8个氨基酸突变，这些突变在非人灵长类和古人类（尼安德特人和丹尼索瓦人）中均不存在，是现代人特有的变异位点。其中，2个突变位点在现代人中已经固定下来，而其他6个位点在人群中仍然是多态的。

　　更有意思的是，这一基因中有4个多态位点在东亚人群中呈现高频率，这和包括中国、日本、蒙古人在内的东亚人脑容量的增大有着密切联系，而在欧洲和非洲人群中，这4个多态位点频率很低。

　　“在人种角度，我们的研究结果显示，CASC5在东亚人群的突变选择拥有更大的灰质容量”（观察者网注：“灰质”是构成大脑皮层的主要成分，由神经元细胞的细胞体聚集而成），研究人员在《人类遗传学杂志》发表的论文表示，“相反，在欧洲和非洲人群中并未发现这一选择信号”。

　　“但这个现象究竟为何发生，现在还尚未充分调查清楚”，他们补充道。

　　除了气候原因，其他的外界因素也可能会促使这一选择的发生，这包括社会结构以及文化偏好，宿兵教授称，不过这些理论仍在猜测阶段，“精确的答案需要进一步的研究”。

>宿兵

　　宿兵表示，这一调查并不能表明亚洲人比其他人群更聪明。“科学研究未能找到任何证据支持人种之间存在智力差异。”

　　不过，他表示，科学家普遍同意人类为获取更大的大脑而作出了巨大牺牲。

　　据悉，大脑需要消耗大量的能量，而更大的大脑使得生育更为艰难，并消耗身体其他部位的资源，这就产生了很多例如体力下降等问题。欧洲人普遍比亚洲人更壮、体型更大，宿兵称，但是体型上的差异是否与大脑大小相关，这需要进一步的研究。

　　“达尔文选择理论在今天可能仍然适用，但我认为，人种之间脑容量的差异，将最终因如今世界范围内的基因交换而消失”（观察者网注：达尔文选择理论即适者生存，不适者被淘汰）

　　另一个在北京的人类学家称，这一研究解决了人类进化史上一个重要，但敏感的议题。“这些研究成果可能会引发种族主义争论”，这位匿名的人类学家表示。

　　研究数据表明，基因突变位点在南亚人群中也呈现高频率态势，这位人类学家称，对他们展开相关调查将会十分有趣。如果他们的大脑也顺应了达尔文正选择理论，大脑变得更大，那么这可能意味着，迁移至离非洲更远地方的人类，他们的大脑发育得更大。

>责任编辑：郑汉星

文章关键词：
大脑 东亚

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