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Duration:06:09
Uploaded:2018-12-07
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We know how to clone animals, so why aren't we saving endangered species by cloning their populations?

Hosted by: Hank Green

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Sources:

https://www.worldwildlife.org/species/directory
http://www.sandiegouniontribune.com/news/environment/sdut-rhino-cloning-stem-cells-san-diego-zoo-safari-park-2014dec20-story.html
http://dolly.roslin.ed.ac.uk/facts/the-life-of-dolly/index.html
https://www.ed.ac.uk/roslin/about/dolly/facts/cloning
https://www.britannica.com/list/cc-the-first-cloned-cat
http://time.com/3822573/snuppy/
https://www.cell.com/cell/fulltext/S0092-8674(18)30057-6
http://www.cnn.com/2001/NATURE/01/12/cloned.gaur/index.html
https://www.sciencemag.org/news/2003/04/banteng-cloned
https://www.theguardian.com/science/2015/aug/05/iran-scientists-clone-endangered-mouflon-domestic-sheep
https://www.scientificamerican.com/article/cloning-endangered-animals/
https://www.smithsonianmag.com/science-nature/why-cloning-your-dog-so-wrong-180968550/
https://www.theverge.com/2018/4/6/17175936/northern-white-rhino-de-extinction-stem-cells-sudan
https://www.fda.gov/animalveterinary/safetyhealth/animalcloning/ucm055513.htm
https://www.ncbi.nlm.nih.gov/pubmed/14733744
https://www.amnh.org/explore/ology/earth/ask-a-scientist-about-our-environment/should-we-clone-endangered-animals
https://www.scientificamerican.com/article/george-church-de-extinction-is-a-good-idea/
https://www.techtimes.com/articles/228655/20180526/scientists-to-clone-entire-northern-white-rhino-population-from-frozen-cells.htm
https://news.nationalgeographic.com/2015/08/150818-plague-yosemite-campground-cases-science/150820-giant-pandas-national-zoo-animals-science/
https://vcahospitals.com/know-your-pet/estrus-cycles-in-cats
https://institute.sandiegozoo.org/science-blog/rhinos-and-reproduction
https://www.theatlantic.com/science/archive/2018/05/how-to-impregnate-a-rhino/561455/
https://phys.org/news/2006-10-tube-rhinos.html
http://wwf.panda.org/knowledge_hub/endangered_species/rhinoceros/african_rhinos/white_rhinoceros/
https://www.nature.com/news/stem-cell-plan-aims-to-bring-rhino-back-from-brink-of-extinction-1.19849
https://qz.com/913682/a-harvard-university-scientistss-attempt-to-resurrect-a-wooly-mammoth-raises-ethical-questions/
http://bio1220.biology.gatech.edu/?page_id=53
https://onlinelibrary.wiley.com/doi/full/10.1111/mam.12138

Images:

http://www.thinkstockphotos.com/image/stock-illustration-african-animals/599878306
https://commons.wikimedia.org/wiki/File:Dolly_face_closeup.jpg
https://commons.wikimedia.org/wiki/File:Indian_Gaur_from_anaimalai_hills_JEG5290.jpg
https://commons.wikimedia.org/wiki/File:Pyrenean_Ibex.png
http://www.thinkstockphotos.com/image/stock-illustration-animal-cloning/985639976
http://www.thinkstockphotos.com/image/stock-photo-great-panda-bear-sitting-at-the-rainforest/865015440
http://www.thinkstockphotos.com/image/stock-photo-homeless-cat-on-the-street/816253988
https://commons.wikimedia.org/wiki/File:One_horn_Rhino_in_Kaziranga_national_park.jpg
http://www.thinkstockphotos.com/image/stock-photo-sheeps-in-green-rural-meadow-south-island-new/486007934
http://www.thinkstockphotos.com/image/stock-photo-eyes-of-the-tiger/544355522
http://www.thinkstockphotos.com/image/stock-photo-ranger-with-firearm-face-to-face-rhino/544808324
https://commons.wikimedia.org/wiki/File:Bumi_Hills_Anti-Poaching_Unit_Protecting_Elephants_in_Zimbabwe.jpg
http://www.thinkstockphotos.com/image/stock-photo-rhino-mother-african-lowveld-savanna-calf/838552492
Thanks to Skillshare for supporting this episode of SciShow. [♪ INTRO].

Tigers, gorillas, rhinos, it seems like there are a lot of animals on the endangered species list these days. But we know how to clone animals.

So if the problem is too few rhinos, and if we know how to make more rhinos, problem solved, right? Well, there actually are people working on cloning endangered animals. 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.

The first mammal cloned from adult cells was Dolly the sheep back in 1996, and since then scientists have cloned a lot of different things, like cats, dogs, and even monkeys. And it didn’t take long for endangered animals to get on that list. In the early 2000s, for example, researchers cloned a type of wild cow called the gaur.

And they went on to clone other endangered cattle, wild sheep, and even an extinct wild goat. But, as cool as these achievements were, none of them ended up really increasing the species’ numbers. That’s because, despite what movies might suggest, you can’t just order up an army of clones.

To clone something, you typically need more than just some DNA from the original creature. You also need an egg cell to put that DNA into to create an embryo. Then that embryo needs to be implanted in a surrogate mother to develop.

You can’t just do this in a petri dish. While that all might sound straightforward enough, getting those eggs in the first place can be difficult and risky for the animal. 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.

Humans generally ovulate in regular, frequent cycles, but not all animals do. Pandas only ovulate once a year, for example, and there are animals like cats that only ovulate after mating. We can sometimes use hormone injections to kick start ovulation, but each animal may need different doses or a different mix of hormones.

And then you still have to get the eggs. Take rhinos, for example. 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.

I won’t. I mean sure, you can sedate her. Which is definitely what the researchers do.

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, and not every individual animal is healthy enough to undergo all that. And also, you need to collect a lot of eggs.

The DNA-egg cell fusion doesn’t always work right, so for each viable embryo, you might need hundreds of egg cells. And even if you go through all of that, you still need surrogates to carry the pregnancy. Like collecting eggs, that requires knowledge about the animal’s reproductive biology, as well as lots of healthy female animals; more than just the number of clones you want to make.

Because unfortunately, not every implantation takes and develops into a healthy offspring. For plentiful species, or ones we know really well, like cows or sheep, those might not be big problems. But for endangered species, like tigers or rhinos, there may not be enough female animals to work with.

The good news is that there are ways to kind of cheat. You can sometimes use eggs or mothers from more common, closely related species, for example. The baby gaur’s surrogate mom was actually a regular cow named Bessie.

Because, of course, all cows are named Bessie, apparently. But hybrid embryos can have extra problems during development. Scientists are working on an alternative to all this: a way to make eggs and sperm by genetically reprogramming frozen tissue samples.

So one day we might be able to make a lot of eggs without needing a lot of female animals. But that’s still in the very early stages and the process will likely need to be customized for each animal. Now, it’s possible that we might figure out how to solve all of these challenges.

But even if we could clone any animal we wanted, it might not be the fix we were looking for. For one thing, even though cloning might increase the number of animals, you could still end up with a loss of genetic diversity because they’d all be genetically identical. That’s bad because the population could effectively become inbred, which can leave them vulnerable to diseases or genetic disorders.

If you have frozen tissues from a lot of different individuals, 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. The real problem with cloning endangered animals is that it won’t stop the poachers, habitat loss, or myriad other things driving these species extinct in the first place. Cloning is very expensive, and some researchers have pointed out it’s probably cheaper and more effective to spend that money on fighting poaching, creating new nature reserves, or other, more traditional conservation efforts.

Still, scientists working on cloning remain optimistic that it could one day become a really useful tool for conservation, like to reintroduce lost genes or a last lifeline to save species whose numbers have dwindled to just a handful. But for now, we’ll have to make all of our tigers and rhinos the old fashioned way. Cloning animals in the real world: super tricky, but cloning pictures of animals is something anyone can learn to do well, especially with a little help from one of the amazing Photoshop classes offered by Skillshare.

But if you really want to up your Photoshop-art game, you might want to check out this Skillshare course by lifestyle journalist Helen Bradley on how to make surrealist collage effects. In it, Helen explains how you can use different Photoshop tools to split apart an image and make really wacky art, sort of like the prints by the artist featured in the episode, Julia Geiser. What I love about this class is that, as the title suggests, Helen goes through everything clearly and quickly, so you really can take the class over your lunch break!

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. Right now, Skillshare is offering SciShow viewers 2 months of unlimited access for free. And they have more than 20,000 classes to choose from, so no matter what hobby you want to pursue, there’s probably a Skillshare course for you to take.

And you’ll be supporting SciShow while you do it. You can follow the link in the description to check it out! [♪ OUTRO].