Cloned mice created from freeze dried skin cells in world first

In a world first, researchers have created cloned mice from freeze dried skin cells.

The breakthrough paves the way for countries to store skin cells from animals as an insurance policy, as the cells can be used to create clones that boost the species' genetic diversity if it becomes threatened with extinction in the future.

Many dwindling species suffer from inbreeding that drives up the risk of birth defects, but the loss of genetic diversity can also make them more vulnerable to other threats.

The cells are kept in liquid nitrogen in order to be safe, but if there is a power outage or the liquid nitrogen is not regularly topped up, the cells will melt and become useless. Clones can be created using freeze dried sperm, but they can't come from all animals.

If these cells can be preserved without liquid nitrogen using freeze-drying technology, it will allow genetic resources from around the world to be stored cheaply and safely. Developing countries will be able to keep their own genetic resources. Even if only males survive, this technology can be used to make females.

Researchers froze dried skin cells from mouse tails and kept them for up to nine months before attempting to clone them. The scientists were able to create early stage cloned embryos by taking the dead cells and putting them into mouse eggs.

Stem cells were created through the use of blastocysts, early stage mouse embryos. Stem cells were inserted into mouse eggs that were emptied of their own nucleus, leading to embryo creation. The first cloned mouse was named Dorami and it was followed by 74 more. The clones were bred with normal mice to see if they had healthy fertility. They all had litters.

The process is inefficient and fails to create healthy female and male mouse pups. Female mice are born from cells obtained from male animals when the Y chromosomes are lost. The authors write that it would be possible to produce females and naturally preserve the species if the same treatment could be done.

As scientists prepare to nurture offspring from the world's first cloned black footed ferret, they are also trying to boost the species' genetic diversity. Thirty five years ago, the animal was cloned from frozen cells.

Being able to store genetic material is important to maintain samples of species. She said it was important to show the freeze-dried cells could be stored indefinitely if they were to provide a long-term solution.