• Question: Scientists have discovered the DNA of mammoths on their bones and may be able to reclone mammoths and bring them back on Earth. How can they reclone mammoths from a swob of DNA?

    Asked by 284heab47 to Billy, Louise, Naomi, Rachel, Urvashi on 15 Mar 2015.
    • Photo: Naomi Green

      Naomi Green answered on 15 Mar 2015:

      Hello 284heab47 🙂

      I hope you have had a good weekend. I’m looking forward to another week of IAEGMOOH! 🙂

      I didn’t know the answer to this question but it is a really interesting one so I looked it up. Scientists have known for some time how to clone an animal. Dolly the sheep was the first animal to be cloned in 1996. Each cell in the body has something called a nucleus, which contains the DNA of that animal, and all the information needed to reproduce them. To clone an animal an egg cell is taken from a donor animal and the nucleus of the donor animal is removed. It is then replaced with the nucleus and DNA of the animal to be cloned. Scientists do a few chemical tweaks and soon the egg cell behaves just like a newly fertilised egg cell, which starts to divide into an embryo. This embryo is then implanted into the donor animal and it develops just like a normal baby and the donor animal gives birth to it.

      The challenge with cloning a Mammoth is getting good enough quality DNA. They have to be able to extract a whole nucleus from a cell which has not been degraded by time and being frozen. Even if we had a whole nucleus to clone it would have to be implanted in an animal to develop into a baby mammoth. The closest animal we currently have to a mammoth is an elephant, but elephants themselves are at risk of being extinct so should we be involving them in such a project? What would we do with a cloned mammoth, where would it live? There are lots of ethical questions to answer, as well as scientific ones before you will see an actual cloned mammoth!

    • Photo: Louise France

      Louise France answered on 16 Mar 2015:

      Hey 284heab47 🙂

      I work with cells quite a lot, so carrying on from Naomi I just wanted to explain why the cloning may be really difficult.

      Biological systems such as the Mammoth, humans, cells etc are largely made up of water. Pure water freezes at zero degrees, but because the water in our bodies is mixed with sugars, salts and proteins, it takes a much lower temperature to make us freeze…thats why our freezers at home tend to be set to -8 degrees and not zero.

      As water freezes it starts to form ice crystals, and if the mammoth was cooled slowly, which it probably was (by slowly i mean it didnt go from 37 degrees to -20 degrees in a matter of minutes, it probably took days for it to freeze), then really big ice crystals would form (this is called nucleation). As the ice crystals form they take up more and more space and cause the cells in the mammoth to swell, and eventually will cause the membranes to burst as the pressure inside the cell is too great for the membrane to withstand. This is called cell lysis, and all of the important DNA from the nucleus will leak out – the cell has died and burst!

      So whilst the scientists discovered DNA on the mammoth bones, it will be really difficult for them to find cells that contain intact DNA for the mammoth. They wont have the whole code that they need to create a ‘test-tube’ mammoth, just little snippets.

      More so, as the mammoth defrosted, all the ice crystals will have melted. If the scientists leave the defrosted mammoth as it is, it will start to decay and will rot (and get really stink), so the likelihood is that they will freeze it again…causing the ice crystals to form again which will continue to burst open the cells! It’s a vicious circle!

      hope that makes sense 🙂

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