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Thanks to Skillshare for supporting this episode of SciShow.
感谢Skillshare对本期《科学秀》的大力支持。
Tigers, gorillas, rhinos, it seems like there are a lot of animals on the endangered species list these days.
老虎、大猩猩、犀牛，如今濒危动物名单上的动物似乎有很多。
But we know how to clone animals. So if the problem is too few rhinos, and if we know how to make more rhinos, perhaps problem solved, right?
但是我们知道怎样克隆动物。因此，如果问题是犀牛数量太少，而且我们也知道怎样培育更多犀牛，或许问题就解决了，不是么？
Well, there actually are people working on cloning endangered animals.
好吧，其实有人在致力于克隆濒危动物。
But, it is not as easy as you might think, and in the end, it still won't fix the problems that made those species endangered in the first place.
但是这没有大家所想的那么容易，并且最终，克隆还是无法解决物种灭绝的根本问题。
The first mammal cloned from adult cells was Dolly the sheep back in 1996,
首只从成年细胞中人工克隆过来的动物是1996年的克隆羊多利，
and since then scientists have cloned a lot of different things, like cats, dogs, and even monkeys.
自那时起，科学家们就克隆过了很多不同的物种，比如猫和狗，甚至是猴子。
And it didn't take long for endangered animals to get on that list.
没过多久濒危动物也登上这份名单。
In the early 2000s, for example, researchers cloned a type of wild cow called the gaur.
21世纪初期，研究人员克隆了一种野生牛—白肢野牛。
And they went on to clone other endangered cattle, wild sheep, and even an extinct wild goat.
并且他们继续克隆了其他濒危牲畜、野羊，甚至是一种灭绝的野山羊。
But, as cool as these achievements were, none of them ended up really increasing the species' numbers.
虽然取得的成就很棒，但最终这些动物的物种数量也没能增加。
That's because, despite what movies might suggest, you can't just order up an army of clones.
那是因为，虽然电影里可能这么演了，但你无法下令克隆出一大群克隆生物。
To clone something, you typically need more than just some DNA from the original creature.
要克隆某物，你需要的不仅仅是原生物的一些DNA。
You also need an egg cell to put that DNA into to create an embryo.
你还需要一颗卵子将DNA植入其中以创造出一个胚胎。
Then that embryo needs to be implanted in a surrogate mother to develop. You can't just do this in a petri dish.
然后这个胚胎需要植入到一个代孕母亲体内才能发育。这一步无法在有盖培养皿中完成。
While that all might sound straightforward enough, getting those eggs in the first place can be difficult and risky for the animal.
虽然所有这些听起来够简单了，但要获取那些卵子很困难，对动物而言也有风险。
To know how to get eggs, you need to know a lot about that specific animal's reproductive biology, like when they ovulate, or grow and release egg cells.
要知道如何获取卵子，你需要了解很多关于这种动物的生殖生物学，比如它们何时排卵何时生长以及何时分泌卵细胞。
Humans generally ovulate in regular, frequent cycles, but not all animals do.
人类通常是定期频繁排卵，但有的动物不是。
Pandas only ovulate once a year, for example, and there are animals like cats that only ovulate after mating.
例如，熊猫一年只排卵一次，像猫之类的动物只在交配后排卵。
We can sometimes use hormone injections to kick start ovulation, but each animal may need different doses or a different mix of hormones.
有时我们可以利用荷尔蒙注射引发排卵，但是每种动物需要的注射剂量不同，所需的荷尔蒙混合也可能不同。
And then you still have to get the eggs. Take rhinos, for example.
然后我们还是需要获取卵子，以犀牛为例。
Like, you try convincing a 1,700 kilogram ovulating rhino to let you collect eggs from inside her using a custom-designed, one-and-a-half-meter-long device.
比如，你要试图说服一只1700公斤的排卵犀牛允许你使用一种长1.5米的定制设备刺入它的体内收集卵子。
I won't. I mean sure, you can sedate her. Which is definitely what the researchers do.
我不会。我是说当然可以给她注射镇定剂，研究人员肯定就是这么做的。
But sedation also carries risks. All and all, getting eggs from animals may involve multiple hormonal injections and the use of anesthetics or surgical procedures,
但是镇定剂也携带风险。总之。要从动物体内获取卵子或许要用到多次荷尔蒙注射以及麻醉药或手术治疗，
and not every individual animal is healthy enough to undergo all that. And also, you need to collect a lot of eggs.
而且不是每种动物的健康状况都足以完成所有这些步骤。还有，你需要收集大量卵子。
The DNA-egg cell fusion doesn't always work right, so for each viable embryo, you might need hundreds of egg cells.
DNA-卵细胞融合并非总能成功，因此，要生成一个有用胚胎，你或许需要数百个卵细胞。
And even if you go through all of that, you still need surrogates to carry the pregnancy.
即便你完成了所有这些步骤，你还是需要代孕。
Like collecting eggs, that requires knowledge about the animal's reproductive biology,
像收集卵子一样，这一步需要了解关于动物生殖生物学的知识，
as well as lots of healthy female animals; more than just the number of clones you want to make.
以及大量的健康雌性动物；不仅仅是你想克隆出的数量而已。
Because unfortunately, not every implantation takes and develops into a healthy offspring.
因为很不幸，并非每一次的移植都能发育成健康的后代。
For plentiful species, or ones we know really well, like cows or sheep, those might not be big problems.
对于数量丰腴的物种而言，或者对于那些我们足够了解的物种，如牛或羊，或许那些不是什么大问题。
But for endangered species, like tigers or rhinos, there may not be enough female animals to work with.
但是对濒危动物，比如老虎或犀牛来说，雌性动物数量或许根本不足以进行克隆。
The good news is that there are ways to kind of cheat.
好消息是有蒙混的方法。
You can sometimes use eggs or mothers from more common, closely related species, for example.
例如，有时候可以利用更加普通的近缘种代替。
The baby gaur's surrogate mom was actually a regular cow named Bessie.
野牛宝宝的代孕母亲其实是一只名为贝茜普通奶牛。
Because, of course, all cows are named Bessie, apparently. But hybrid embryos can have extra problems during development.
当然因为所有奶牛都叫贝茜。但是杂交胚胎在发育期间还有其他的问题。
Scientists are working on an alternative to all this: a way to make eggs and sperm by genetically reprogramming frozen tissue samples.
科学家们正致力于一种所有问题的替代方法：一种通过基因改造冷冻组织样本制造卵子和精子的方法。
So one day we might be able to make a lot of eggs without needing a lot of female animals.
所以或许有一天我们可以在不需要大量雌性动物的情况下制造出很多卵子。
But that's still in the very early stages and the process will likely need to be customized for each animal.
但是这一方法仍处于非常初期的节段，并且整个进程可能需要为每种动物私人订制。
Now, it's possible that we might figure out how to solve all of these challenges.
现在或许弄清楚如何解决所有这些挑战是有可能的。
But even if we could clone any animal we wanted, it might not be the fix we were looking for.
但即便我们可以克隆出想要的动物，这可能也不是我们所寻找的解决方法。
For one thing, even though cloning might increase the number of animals,
其一是，虽然克隆或许能够增加动物数量，
you could still end up with a loss of genetic diversity because they'd all be genetically identical.
但结果仍有可能会损失遗传多样性，因为它们在基因上都是相同的。
That's bad because the population could effectively become inbred, which can leave them vulnerable to diseases or genetic disorders.
这并不是好事，因为它们可能会近亲交配，让它们无法抵御疾病或遗传病。
If you have frozen tissues from a lot of different individuals,
如果你从很多不同个体中获取了冷冻组织，
you might be able to avoid this issue or even reintroduce genetic variation that's been lost, but that will depend on what you've stockpiled.
你或许能够避免这一问题或是甚至是重新引入失去的基因变异，但是这要取决于你库存的是什么。
The real problem with cloning endangered animals is that it won't stop the poachers, habitat loss,
克隆濒危动物真正的问题在于它无法阻止偷猎者、栖息地的丧失
or myriad other things driving these species extinct in the first place.
或者其他迫使这些物种灭绝的事物。
Cloning is very expensive, and some researchers have pointed out it's probably cheaper and more effective to spend that money on fighting poaching,
克隆非常贵，一些研究人员指出将钱花在打击偷猎者、
creating new nature reserves, or other, more traditional conservation efforts.
创建新的自然保护区或其他更加传统的保护手段上或许更便宜且更高效。
Still, scientists working on cloning remain optimistic that it could one day become a really useful tool for conservation,
科学家们的克隆工作还是很乐观的，也许将来克隆真的可以成为保护的有效工具
like to reintroduce lost genes or a last lifeline to save species whose numbers have dwindled to just a handful.
可以重新引入遗失基因或延长生命周期拯救那些濒临灭绝的物种。
But for now, we'll have to make all of our tigers and rhinos the old fashioned way.
但现在，我们将不得不按照老派的方法培育老虎和犀牛。
Cloning animals in the real world: super tricky, but cloning pictures of animals is something anyone can learn to do well,
在真实世界中克隆动物：超级棘手，但是克隆动物图片每个人都可以学习，
especially with a little help from one of the amazing Photoshop classes offered by Skillshare.
特别是在Skillshare的PS课程的帮助下。
But if you really want to up your Photoshop-art game,
但如果你真的想要提高PS技能，
you might want to check out this Skillshare course by lifestyle journalist Helen Bradley on how to make surrealist collage effects.
你可能想要查看生活方式记者海伦·布兰得利的Skillshare课程—《如何制造出超现实主义拼贴画效果》。
In it, Helen explains how you can use different Photoshop tools to split apart an image and make really wacky art,
在该课程中，海伦将解释如何利用不同PS工具将一幅图分割开来并制作成奇异的艺术，
sort of like the prints by the artist featured in the episode, Julia Geiser.
有点像是朱莉娅·盖泽讲版画的那期课程。
What I love about this class is that, as the title suggests, Helen goes through everything clearly and quickly,
我喜爱这期课程的原因在海伦讲的很清楚，课程也不长，
so you really can take the class over your lunch break!
所以你真的可以利用午餐的时间上上课！
And Helen has a bunch of other quick courses on Skillshare, so you can try your hand at making stylish doodles or drawing furry creatures.
海伦在Skillshare有很多其他小课程，所以你可以尝试画画涂鸦或是画一些毛茸茸的生物。
Right now, Skillshare is offering SciShow viewers 2 months of unlimited access for free.
现在，Skillshare为《科学秀》观众提供2个月的免费无限制权限。
And they have more than 20,000 classes to choose from,
他们有两万多期课程供大家选择，
so no matter what hobby you want to pursue, there's probably a Skillshare course for you to take.
不论你的爱好是什么，都能在Skillshare找到你想上的课。
And you'll be supporting SciShow while you do it. You can follow the link in the description to check it out!
参加课程，支持《科学秀》。你可以点击下方链接进行查看！
