Urednik samog sebe

Šestog jutra, Chiara je pripremila kavu za oboje i sjela u stolicu pokraj akvarija. Pasta je visjela naopako iz kuta stakla, njezino tijelo nježno je pulsiralo. Ruke su joj lepršale oko nje poput usporenog cvijeta.

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

"Postoji još jedna stvar koju ti želim reći," rekla je Chiara, "i želim to reći polako, jer je to najčudnija stvar o hobotnicama koju znam."

"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 je sjedila na rubu.

Polly perched on the rim.

"Hobotnice mogu uređivati vlastitu RNK u stvarnom vremenu," rekla je Chiara. "To je nešto što stalno rade. Nijedna druga životinja to ne čini u mjeri u kojoj to rade hobotnice i nekoliko srodnih glavonožaca."

"Octopuses can edit their own RNA in real time," Chiara said. "It is something they do constantly. No other animal does this at the rate that an octopus and a few related cephalopods do."

Zastala je. Znala je da sljedeći dio zahtijeva pažnju.

She paused. She knew the next part required care.

DNK je dugoročni nacrt životinje. Ne mijenja se mnogo. RNK je radna kopija. Stanica stvara RNK iz DNK kada treba izgraditi protein. Kod većine životinja, RNK gotovo točno odgovara DNK.

DNA is the long-term blueprint of an animal. It does not change much. 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 almost exactly.

Kod hobotnica, RNK ne odgovara. Dok se RNK stvara, stanica prepisuje dijelove. Većina tih izmjena događa se u dijelovima genoma koji grade živčani sustav. Živčani sustav hobotnice, posebno, stalno se izgrađuje i prepravlja tim izmjenama.

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 of the genome that build the nervous system. The nervous system of an octopus, in particular, is built and rebuilt constantly with these edits.

"Zašto?" rekla je Chiara, prije nego što je Polly mogla pitati. "Imamo teoriju. Uređivanje RNK je reverzibilno. Mutacija DNK nije. Hobotnica može prilagoditi svoj živčani sustav u odgovoru na temperaturu vode ili kemiju hrane koju jede. Može prilagoditi svoj mozak u hodu. Cijena je da sam genom, dugoročni nacrt, nije mogao mnogo evoluirati. Vrsta je zapela s istom DNK, manje-više, desecima milijuna godina. Platili su kratkoročnu fleksibilnost dugoročnom stagnacijom."

"Why?" Chiara said, before Polly could ask. "We have a theory. 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 the food it eats. It can tune its own brain on the fly. The cost is that the genome itself, the long-term blueprint, has not been able to evolve much. The species is stuck with the same DNA, more or less, for tens of millions of years. They paid for short-term flexibility with long-term stagnation."

Polly je promatrala Pastu kako pluta. Tijelo hobotnice polako je pulsiralo. Koža blizu očiju treperila je kroz nježan puls ružičastih i blijedih smeđih tonova.

Polly watched Pasta drift. The octopus's body pulsed slowly. The skin near the eyes flickered through a soft pulse of pinks and pale browns.

"Svaka pojedinačna hobotnica," rekla je Chiara, "je malo drugačija životinja od svake druge, na način na koji ti i ja i drugi papagaji nismo. Ista DNK. Ali radni mehanizam se iznova gradi, svaki život, za tu vodu i tu hranu. Oni su individualni mozgovi na način na koji možda nijedna druga životinja na Zemlji nije."

"Each individual octopus," Chiara said, "is a slightly different animal from each 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. They are individual brains in a way that perhaps no other animal on Earth is."

Popila je svoju kavu.

She drank her coffee.

"To je također razlog," rekla je, "zašto dvije hobotnice koje dobiju isti labirint mogu ga riješiti na potpuno različite načine. Pasta je riješila labirint s dvije ruke koje su surađivale. Imali smo drugu hobotnicu prošle godine koja je koristila tri. Imali smo još jednu koja je čekala sat vremena, a zatim ušla ravno s tijelom. Ne rješavaju isti problem s istim mozgom. Svaka ga rješava s mozgom koji su same sebi izgradile."

"It is also why," she said, "two octopuses given the same maze can solve it in completely different ways. Pasta solved the maze with two arms cooperating. We had another octopus last year who used three. We had another who waited an hour and then went straight in with the body. They are not solving the same problem with the same brain. They are each solving it with the brain they have made for themselves."

Pastino oko se otvorilo i zatvorilo. Ruke su lepršale.

Pasta's eye opened and closed. The arms drifted.

Polly je razmišljala o svom mozgu. Nije bio uređen u stvarnom vremenu. Bio je izgrađen jednom, na način na koji se većina mozgova gradi, i sada je jednostavno bio njezin. Nije zavidjela Pasti na fleksibilnosti. Ali jako joj se svidjelo znati da postoje životinje poput Paste.

Polly thought about her own brain. It had not been edited in real time. 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.

Chiara je ustala. "Moram napisati prijedlog za financiranje," rekla je. "Ostani s njom jutro, ako želiš."

Chiara stood up. "I have to go write a grant," she said. "You stay with her for the morning, if you want."

Polly je ostala.

Polly stayed.