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当前位置: Science » 植物&动物 » Science:蝾螈如何再生四肢


摘要 : 长出新肢体的能力可能看起来像是科幻小说的情节,但新研究就展示了像蝾螈和斑马鱼这样的动物是如何实现这一惊人壮举的,以及人类又是如何可能分享让这些动物重新长出肢体的生物构造机制。


长出新肢体的能力可能看起来像是科幻小说的情节,但新研究就展示了像蝾螈和斑马鱼这样的动物是如何实现这一惊人壮举的,以及人类又是如何可能分享让这些动物重新长出肢体的生物构造机制。科学家们早就知道某些鱼类和两栖类拥有再生能力:为了重新长出因饥肠辘辘的捕食者而失去的肢体或翅鳍,它们可以利用伤口处形成的干细胞再生一切——从骨骼到肌肉再到血管。不过,它们是如何在基因水平做到这一切的,还是一个谜。为了弄清楚究竟怎么回事,科学家们截去了两种辐鳍鱼,即斑马鱼和多鳍鱼,以及被称为蝾螈的一种火蜥蜴的部分肢体,所有这些动物都可以再生自己的腿和翅鳍。他们随后比较了截肢部位的核糖核酸(RNA),发现三个物种都共同拥有10个小分子核糖核酸(microRNA),即调节基因表达的小块RNA,而且它们似乎以同样的方式在工作,尽管蝾螈(上图)和鱼类之间的结构有差别。这一发现为一个现有的想法提供了佐证,即这三种“换肢专家”最后一次拥有共同祖先是在约420万年前,这也表明,四肢的生长进化过程是随着时间慢慢累积,而不是各个物种分别自主发育的,研究人员今天在PLOS ONE上这样报告说。这对人类来说意味着什么呢?如果可以对这些微RNA进行编辑,让它们像在蝾螈和鱼上那样工作,那么人类就可能提高自身从重伤中修复的能力。但是,不要指望你会得到金刚狼一样的能力,科学家表示这种基因编辑还有很长的路要走。


How some salamanders regrow their limbs


The ability to grow a new limb may seem like something straight out of science fiction, but new research shows exactly how animals like salamanders and zebrafish perform this stunning feat—and how humans may share the biological machinery that lets them do it. Scientists have long known of the regenerative powers of some species of fish and amphibians: To recreate a limb or fin lost to a hungry predator, they can regrow everything from bone to muscle to blood vessels with stem cells that form at the site of the injury. But just how they do it at the genetic level is a mystery. To figure out what might be happening, scientists amputated the appendages of two ray-finned fish—zebrafish and bichir—and a salamander known as the axolotl, all of which can regrow their legs and fins. They then compared RNA from the site of the amputation. They found 10 microRNAs—small pieces of RNA that regulate gene expression—that were the same in all three species. What’s more, they seemed to function in the same way, despite the structural difference between the axolotl (pictured above) and the fishes. The finding supports an existing idea that the three master limb-replacers last shared a common ancestor about 420 million years ago, and it suggests that the evolutionary process of growing limbs is saved over time, not developed independently in separate species, the researchers report today in PLOS ONE. What does this mean for humans? If these microRNAs can be programmed to work like they do in salamanders and fish, humans could enhance their ability to heal from serious injuries. But don’t expect to get Wolverine-like powers just yet—scientists say such modifications are still a long way off.

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