Scientists create world's first cloned mice using freeze-dried skin cells
Amid warnings of accelerated worldwide extinctions, a group of Japanese scientists has created cloned mice from freeze-dried skin cells. Although cloning is nothing new, this is the first time researchers have been able to clone from freeze-dried skin cells. The new method is expected to help overcome challenges faced in current biobanking methods. The experiment was conducted at the University of Yamanashi.
- The United Nations recently warned us that at least a million species could disappear due to our own doing.
- Scientists have been trying to create a method that would help us in preserving endangered species. The cloning of freeze-dried skin cells by Japanese researchers could be a watershed moment in our quest.
- The process can also be used to improve genetic diversity in species.
First, dried skin cells from mouse tails were frozen for nine months. Though freeze-drying process killed the cells, the researchers found they could still produce early-stage cloned embryos (blastocysts) by inserting dead cells into mouse eggs with nuclei removed. The blastocysts were used to create stem cells that went through another round of cloning. These cells became embryos that surrogate mice carried to term.
The researchers named the first cloned mouse Dorami after the manga character Doraemon. Dorami was followed by 74 more. To check their fertility, nine females and three males were mated with normal mice. All females went on to have litters.
As human-induced extinction of other species is a real issue, facilities have come up globally to preserve samples of endangered species. The samples are usually preserved either through cryopreservation using liquid nitrogen or deep freezing at extremely low temperatures. This method is costly and is vulnerable to power outages. The involvement of sperm and egg cells makes this process less viable in some cases.
Cloning using freeze-dried skin cells of endangered species will make the process of biobanking cheap and safe. The use of skin cells instead of sperm or egg cells makes the process more viable in the case of old or infertile species.
The freeze-drying method is not foolproof though. Freeze-drying damaged DNA in the skin cells. Another issue was the success in creating healthy male and female pups. The success rate was only 0.2% to 5.4%. In some cases, the Y-chromosome was lost and this led to female mice being born out of cells obtained from male animals.