时差N小时 短嘴鳄可以再长牙齿（在线收听）

Fun fact about alligators:they can regrow any of their eightyteeth up to fifty times.

关于短嘴鳄的有趣的事实：它们的八十颗牙齿中任一一颗牙都可以重新生长五十次。

Which is pretty impressive, especially compared to us relatively dentallychallenged humans:

这实在让人惊讶，特别是和我们人类牙齿的相对障碍相比：

when we lose adult teeth, there's no regrowing them.

当我们失去恒牙便再无重生的可能。

But that may change.

但这样的情况可能有所改观。

Hoping to save the toothless among us from being fated to wearingdentures, scientists are studying how alligators regrow teeth and how the same process may beable to work in humans.

为了摆脱我们因没有牙齿而戴上假牙的命运，科学家们正在研究短嘴鳄牙齿再生的机理以及同样的方式如何能够同样作用于人类。

Using X rays and tissue samples, plus lab grown gator tooth cells and computer models, scientistshave learned that for each gator tooth there are two tooth precursors, both of which aretriggered to grow when a mature tooth is lost.

利用X射线和组织样本，加上实验室生长的鳄鱼牙齿细胞和计算机模型，科学家发现每一颗鳄鱼牙齿上均有两个牙前体细胞，当成熟的牙齿脱落，这两个前体就会触发新牙生长。

The growth process begins when a band of tissue called the dental lamina begins to bulge. Thiswakes up stem cells and signaling molecules that kick start new tooth growth. And finally a newtooth grows in to replace the one that was lost.

当一组名为牙板的组织开始膨胀，再生的过程就开始了。这一过程唤醒了干细胞和推动新牙生长的信号分子。最后一颗新牙长出并取代原先那颗失去的牙。

Now, it's difficult to take what nature and evolution have combined to create in one species andsomehow make it happen in another.

现在的问题在于，如何让这个在一个物种上结合了自然和进化的产物发生在另一物种身上。

But we humans do have remnants of dental lamina.

但我们人类仍然有残留的牙板。

Andscientists are trying to figure out how to manipulate it to enable tooth growth in people similar tohow it works in alligators.

科学家们正试图找出如何操作的方法，使人类牙齿生长的机理和短嘴鳄的相似。

We could potentially use that same knowledge to turn off the processesin humans that sometimes cause problems like growing too many teeth or oddly shaped andspaced teeth.

我们很可能利用相同的知识结束人类牙齿生长时常产生的问题的过程，例如长了多余的牙齿，或者龅牙以及间隙牙。

The alligator research is still in the early stages, so regrowing human teeth is still a ways away.

短嘴鳄的研究仍然处于早期阶段，因此人类离牙齿再生的现实还有一定距离。

Butbefore too long, replacing a lost adult tooth may be as simple as growing it back.

但不久的将来，也许替换一颗掉落的恒牙和新长一颗一样简单。