older isn’t as universal a fact of life as we might think.

老化並不如我們想像中是個放睹四海皆準的事實。

Take the naked mole rat. Unlike their less-naked brethren, they don’t appear to age after

以裸鼴鼠為例子。 跟牠們有毛的同類們不一樣，牠們成年後不會隨著

reaching adulthood - years pass, but the rats don’t get weaker, more susceptible to disease,

時間老化－時間過去，但這些老鼠不會變虚弱，不受疾病侵擾，

or wrinkly...at least not any more wrinkly...and they keep on making as many babies as ever.

皮膚也不會長皺紋．．．至少不會長更多皺紋．．．而且牠們一如往常不停繁衍下一代。

Surprisingly, they aren’t any more likely to die in old age than when they’re young

更令人驚訝的是，裸鼴鼠不會因為年紀愈來愈老就比牠們在年輕時更容易死忙。

adults. It’s as if they’ve found the fountain of youth, though perhaps not the fountain

就好像他們找到青春之泉，但也許不是美麗之泉

of beauty. And naked mole rats aren’t alone in not aging: rockfish, lobsters, and bristlecone

在不老方面，裸鼴鼠並不孤单 石斑魚，龍蝦， 及狐尾松

pines also seem to stay forever young...or at least forever middle-aged.

也以乎永遠年輕．．．或至少永遠是中年。

We’re not exactly sure how these species do it, but their anti-aging secret may have

我們不太確定這些物種是怎麼辦到的， 但是牠們抗衰老的秘密可能

to do with their ability to rebuild the DNA caps on their chromosomes. These caps, called

和重建DNA保護套在染色體上的功能有關。這些保護套，叫做

telomeres, are one line of defense against aging in many species. That’s because cells

端粒，是許多物種的一種抵禦衰老的方法。這是因為細胞

need to divide to replace old or dysfunctional cells, but each time they replicate, they

為了取代舊的或無功能的細胞而分裂， 但每次細胞複製，

lose a little bit of DNA from the end of each chromosome. Normally that doesn’t matter,

會從染色體失去一點DNA 。那通常不重要，

since these lost bits come from the telomere end caps that don’t encode important information.

因為這些失去的部分是從不會編碼資訊的端粒的保護套。

But after many replications, the telomeres get trimmed so short that the cells can’t

但經過多次複製會簡短端粒到細胞

afford to lose any more DNA, and they stop replicating.

無法負荷失去更多DNA， 就停止複製。

Age-defying species like naked mole rats, however, pump out high levels of a telomere-rebuilding

然而，抗衰老種類如裸鼴鼠，生產高度的重建端粒酶

enzyme that enables them to keep on replacing old and dysfunctional cells indefinitely.

持續地取代舊的和不正常的細胞。

A few kinds of human cells make this enzyme, but the vast majority don’t. And even if

少数人體細胞能制造这種酶，但絕大多數不能。即使

we could trick the rest into producing it, then we’d have another problem: more replications

我們能誘導其餘的细胞制造酶，接著我們會有其它麻煩：更多的重複

means more chances for mutations that could turn a cell cancerous unlimited replication

意味著更多機會突變會促使細胞癌變無限複製

increases a cell’s chances of becoming cancerous. Naked mole rats don’t care because they

增加细胞變成癌細胞的機會。 裸鼴鼠不在乎，因為他們

seem to be immune to cancer; but we humans certainly aren’t.

似乎對癌症免疫; 但我們人類肯定不是。

However, as amazing as naked mole rats are, they can only pause their aging – the tiny

然而，就算裸鼴鼠如此令人驚歎，他們也只能暫停老化－ 小小的

jellyfish Turritopsis dohrnii can age in reverse. Like butterflies, Turritopsis morph through

燈塔水母卻可以逆轉年齡。就像蝴蝶一樣，燈塔水母

multiple stages during their life cycle. But unlike butterflies, if Turritopsis get wounded

在其生命週期中通過許多階段。但跟蝴蝶不同的是，如果燈塔水母受傷

or if times get tough, they can morph backwards, reverting to their immature polyp form until

或者生存環境變得艱困，牠們可以逆轉變身，回到牠們的不成熟息肉形態，直到

conditions improve. They’re like, real life phoenixes.

情況好轉。牠們就像，現實生活中的鳳凰。

However if humans could somehow imitate Turritopsis’ trick, it might not give us the kind of eternal

但是，如果人在某種程度上能夠模仿燈塔水母的技能，它也許不會帶來那種我們

youth we’d be looking for… for one thing, melting into an amorphous blob where our cells

一直追尋的青春．．．首先，融化成一種沒有固定形狀的一團

are reorganized and reprogrammed with new functions would not only be a mess; it would

我們的細胞在其中重整和改組新功能，簡直不只是一團遭；

likely turn our brain cells into skin or muscle cells - and vice versa - erasing our memories

那將會把我們的腦細胞變成皮膚或肌肉細胞- 反之亦然- 刪除我們的記憶

and our sense of self. And no matter what, eternal youth wouldn’t

及我們的自我意識。而無論如何，永恆的青春不會

make us invincible - in fact, the longer a creature lives, the more time it has to get

使我們立於不敗之地- 事實上，生物活得愈久，牠就必須經歷更久的

chomped, starved, or smooshed. So eventually, every naked mole rat, pine tree, and jellyfish

咀嚼，挨餓，或壓擠。所以到最終，即使是裸鼴鼠，狐尾松和水母

will ultimately meet its end - because it’s possible to be immune to aging, but not to death.

也要面對終點，因為可能可以避免老化，但無法避免死亡。