自我编辑者

第六天早上，Chiara为她们俩煮了咖啡，然后坐在水箱旁边。Pasta倒挂在玻璃的一角，她的身体轻轻地鼓动着，手臂像慢慢绽放的花朵一样漂浮着。

On the sixth morning, Chiara made coffee for both of them and sat down beside the tank. Pasta was hanging upside down from a corner of the glass. Her body bell pulsed gently. Her arms drifted around her like a slow flower.

“还有一件事我想告诉你，”Chiara说，“我想慢慢地说，因为这是我所知道的关于章鱼最奇怪的事情。”

"There is one more thing I want to tell you," Chiara said, "and I want to tell it slowly, because it is the strangest thing about octopuses I know."

Polly坐在边缘。

Polly perched on the rim.

“章鱼可以实时编辑自己的RNA，”Chiara说，“没有其他动物能像它们这样频繁地做到这一点。”

"Octopuses can edit their own RNA in real time," Chiara said. "No other animal does this at the rate they do."

DNA是动物的长期蓝图，一生中变化不大。RNA是工作的副本。当细胞需要制造蛋白质时，就会从DNA中制作RNA。在大多数动物中，RNA与DNA完全匹配。

DNA is the long-term blueprint of an animal. It does not change much in a lifetime. RNA is the working copy. The cell makes RNA from DNA when it needs to build a protein. In most animals, the RNA matches the DNA exactly.

在章鱼中，RNA并不匹配。当RNA正在被制造时，细胞会重写其中的一部分。这些编辑大多发生在构建神经系统的部分。

In octopuses, the RNA does not match. As the RNA is being made, the cell rewrites parts of it. Most of these edits happen in the parts that build the nervous system.

“为什么呢？”Chiara说，“RNA编辑是可逆的，而DNA突变不是。章鱼可以根据水温或食物的化学成分调整其神经系统。它调整自己的大脑。代价是这个物种本身无法进化太多。它们用短期的灵活性换来了长期的稳定性。”

"Why?" Chiara said. "RNA editing is reversible. DNA mutation is not. An octopus can adjust its nervous system in response to the temperature of the water or the chemistry of its food. It tunes its own brain. The cost is that the species itself has not been able to evolve much. They paid for short-term flexibility with long-term stability."

Pasta漂浮着，她眼睛附近的皮肤闪烁着柔和的粉色和浅棕色。

Pasta drifted. Her skin near the eyes flickered through soft pinks and pale browns.

“每只章鱼，”Chiara说，“在某种程度上都是与其他章鱼不同的动物，而你我和其他鹦鹉则不是。相同的DNA，但每一生的工作机制都是为那片水和那种食物重新构建的。”

"Each individual octopus," Chiara said, "is a slightly different animal from every other one, in a way that you and I and other parrots are not. The same DNA, but the working machinery is built fresh, every life, for that water and that food."

Polly想到了自己的大脑。它是按照大多数大脑的方式建造的，现在只是属于她的。她并不羡慕Pasta的灵活性，但她非常喜欢知道像Pasta这样的动物存在。

Polly thought about her own brain. It had been built once, the way most brains are built, and was now simply hers. She did not envy Pasta the flexibility. But she liked very much knowing that animals like Pasta existed.