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  • Either Douglas Adams was right, and mice are protrusions of hyperintelligent pandimensional

  • beings into our universe, or we are on our way to making Pinky and the Brain a reality...

  • Hey science news fans! I’m Dr. Kiki from This Week in Science here for DNews.

  • Where did people get our big brains? Evolutionary research suggests that something happened

  • in our past triggering a rapid expansion of a part of our brains called the neo-cortex,

  • which is involved in higher level cognitive functions like language and math.

  • It could have been a cultural advancement, like cooking, that freed up more energy for

  • the brain. But, the many underlying genetic factors that differentiate the human brain

  • from our nearest primate cousins are virtually unknown.

  • Studies scanning the human genome for genes that might be the root of our unique brain

  • have found many human-specific genetic sequences that regulate the activity of genes. These

  • sequences are calledenhancers’. But, the question remained whether there any enhancers

  • in the human genome that specifically influence the development of the human brain?

  • In a study published on February 19th, 2015 in the journal Current Biology, scientists

  • reported that they had discovered a human gene enhancer called Human-accelerated regulatory

  • enhancer 5, or HARE 5, that does just that. In mice, it led to the development of larger

  • brains.

  • Transgenic mouse embryos were created using either a chimpanzee version of HARE 5 or the

  • human version of the gene enhancer. When the two groups of mice were compared, it was obvious

  • that the human HARE 5 activated earlier in development, and triggered a more robust response

  • than the chimp version.

  • The young neural cells in the brain, called neural progenitor cells, proliferated more

  • quickly under the influence of human HARE 5, which led to bigger brains. Twelve percent

  • bigger than those with chimp HARE 5 to be exact.

  • But, do bigger brains mean that these HARE 5 mice would be smarter than the average mouse?

  • That’s outside the scope of this particular study, but a study published in the Journal

  • of Neuroscience in December, 2014, injected immature human glial cells, the cells that

  • pack in around neurons in the brain, into the brains of baby mice. Not only did these

  • human cells completely usurp the mouse glial populations, but also resulted in four times

  • better performance on a memory test than control mice.

  • It’s thought that the human cells allowed the mouse brains to work more efficiently,

  • but didn’t actually change how they functioned. So, the mice were still mice, just a little

  • smarter thanks to the human glial cells.

  • Yet, this research raises the question of how far we should go when mixing human cells

  • and genes with other animal species. Our ability to learn by studying humans is limited because

  • we can’t very well go around chopping people up in the name of science. Since the advent

  • of stem cell research and genetic manipulation we have gained the ability to mix our cells

  • and genes within other animals, and see how they work. Animals with human-like organs

  • and cells make research that would otherwise be impossible possible.

  • The HARE 5 researchers plan to continue this research, so we will very likely find out

  • whether this gene enhancer results in smarter mice. The point, however, is not to make a

  • better, faster, stronger mouse, or even to make human-like mice. The point of this line

  • of research is to discover more about the human brain, to discover what makes it different,

  • and to learn why some people get neurodegenerative disorders when others don’t, so that we

  • can individualize treatments appropriately.

  • Will research in this vein help humanity, or will it inevitably lead to hyperintelligent

  • mice taking over the Earth? Will we bow down to our mousey overlords?

Either Douglas Adams was right, and mice are protrusions of hyperintelligent pandimensional

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B2 中上級

マウスに人間の脳を与えることで何が学べるのか? (What Can We Learn By Giving A Mouse A Human Brain?)

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    黃冠瑋 に公開 2021 年 01 月 14 日
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