(Sarah Knapton) Humans may one day have the ability to regrow limbs after scientists at Harvard University uncovered the DNA switch that controls genes for whole-body regeneration.
（莎拉·卡纳顿）哈佛大学的科学家发现了控制全身再生基因的 DNA 开关后，人类可能有一天能够再生肢体。
Source – Yahoo News
Some animals can achieve extraordinary feats of repair, such as salamanders which grow back legs, or geckos which can shed their tails to escape predators and then form new ones in just two months.
Planarian worms, jellyfish, and sea anemones go even further, actually regenerating their entire bodies after being cut in half.
Now scientists have discovered that that in worms, a section of non-coding or 'junk' DNA controls the activation of a 'master control gene' called early growth response (EGR) which acts like a power switch, turning regeneration on or off.
现在，科学家们发现，在蠕虫体内，一段非编码或"垃圾"DNA 控制着一种称为"早期生长反应"(early growth response，EGR)的"主控基因"的激活，这种基因就像一个电源开关，控制着再生的开启或关闭。
"We were able to decrease the activity of this gene and we found that if you don't have EGR, nothing happens," said Dr Mansi Srivastava, Assistant Professor of Organismic and Evolutionary Biology at Harvard University.
"The animals just can't regenerate. All those downstream genes won't turn on, so the other switches don't work, and the whole house goes dark, basically."
The studies were done in three-banded panther worms. Scientists found that during regeneration the tightly-packed DNA in their cells, starts to unfold, allowing new areas to activate.
But crucially humans also carry EGR, and produce it when cells are stressed and in need of repair, yet it does not seem to trigger large scale regeneration.
Scientists now think that it master gene is wired differently in humans to animals and are now trying to find a way to tweak its circuitry to reap its regenerative benefits.
Post doctoral student Andrew Gehrke of Harvard believes the answer lies in the area of non-coding DNA controlling the gene. Non-coding or junk DNA was once believed to do nothing, but in recent years scientists have realised is having a major impact.
哈佛大学后教授的博士生 Andrew Gehrke 认为答案在于控制基因的非编码 DNA 区域。非编码或垃圾 DNA 曾经被认为什么也做不了，但是近年来科学家已经意识到正在产生重大影响。
"Only about two percent of the genome makes things like proteins," added Mr Gehrke said. "We wanted to know: What is the other 98 percent of the genome doing during whole-body regeneration?
"I think we've only just scratched the surface. We've looked at some of these switches, but there's a whole other aspect of how the genome is interacting on a larger scale, and all of that is important for turning genes on and off."
Marine animals, such as the moon jellyfish, are masters of regeneration and some have been found to clone themselves after death.
In 2016, a Japanese scientist reported that three months after the death of his pet jellyfish, a sea anemone-like polyp rose out of the degraded body, and then astonishingly aged backwards, reverting to a younger state.
In the 1990s, scientists in Italy discovered that the Turritopsis dohrnii jellyfish switches back and forth from being a baby to an adult, resulting in its nickname, the immortal jellyfish.
Dr Srivastava added: "The question is: If humans can turn on EGR, and not only turn it on, but do it when our cells are injured, why can't we regenerate?" added Dr Srivastava.
斯利瓦斯塔瓦博士补充说:"问题是: 如果人类可以启动 EGR，不仅可以启动它，而且可以在细胞受伤时启动，为什么我们不能再生呢?" 斯利瓦斯塔瓦博士补充道。
"It's a very natural question to look at the natural world and think, if a gecko can do this why can't I?
"The answer may be that if EGR is the power switch, we think the wiring is different. What EGR is talking to in human cells may be different than what it is talking to in the three-banded panther worm."
"答案可能是，如果 EGR 是电源开关，我们认为线路是不同的。EGR在人类细胞中所说的可能与在三带黑豹蠕虫中所说的不同。"
The research was published in the journal Science.