Japanese scientists are cloning mice using dried cells with the aim of stopping the extinction of the animals

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Japanese scientists have cloned mice using freeze-dried cells as part of a new technology that is still in its infancy, comparable to the research that resulted in the cloning of the famous sheep “Dolly”, which the scientific community hopes to find solutions that allow the preservation of the species and overcoming the current challenges associated with its use the Biobank method, at a time when the United Nations has warned that the extinction of animals in the world is accelerating, and at least one million species may disappear due to the consequences of human activities such as climate change.

Japanese scientists have created cloned mice using freeze-dried cells, a technique they believe could one day help preserve the species and overcome current challenges associated with biobanking.

The United Nations has warned against it Extinction of animals It is accelerating worldwide, and at least one million species could disappear due to the effects of human activities such as climate change. In order to face this danger, specialized facilities for the preservation of samples of endangered species have spread around the world, with the aim of preventing their extinction through future cloning.

These samples are generally preserved by cryopreservation using liquid nitrogen or at very low temperatures, two methods that can be expensive and susceptible to power outages. Samples usually include sperm or eggs that are difficult or impossible to obtain from older or infertile animals.

A group of scientists from Japan’s Yamanashi University wanted to see if they could find solutions to these problems by using a freeze-drying technique on somatic cells, or cells other than sperm or eggs, in an effort to produce clones.

Cloned mice mate and give birth

The scientists conducted experiments on two types of mouse cells and found that, although freeze-drying killed them and caused significant damage to their DNA, they could still produce cloned blastocysts, the ball of cells that develop into an embryo. From these cysts, the scientists extracted the stem cell sequences that they used to create 75 cloned mice.

And one of the mice lived for a year and nine months, while the scientists managed to marry a female and a male cloned from two naturally born mice, and they got normal baby mice. Cloned mice produced fewer offspring than would be expected from naturally born mice, while a line of stem cells developed from male cells was produced only in cloned female mice.

In this context, said Teruhiko Wakayama, a professor at Yamanashi University’s Faculty of Life and Environmental Sciences who helped prepare the study published in the journal “Nature Communications“Evolution shouldn’t be difficult,” he told AFP. “We believe that in the future we will be able to reduce deformities and increase birth rates by looking for factors that prevent freeze-drying, as well as by improving drying methods.”

Some other obstacles have also appeared, for example that the success rate of cloning mice from cells stored in liquid nitrogen or at very low temperatures is between 2 and 5 percent, while the success rate of the freeze-drying technique is limited to only 0.02 percent.

Wakayama said the technology is still in its early stages, comparing it to research work that resulted in the cloning of “Dolly” the sheep, a process that succeeded after more than two hundred attempts. “We think the most important thing is that the cloned mice were created from freeze-dried somatic cells and that we have made great progress in that area,” he said.

Storage of genetic resources

While the technology is unlikely to completely replace cryopreservation, it represents “an important advance for scientists interested in global biodiversity threatened by biobanking methods,” says Simon Clulow, senior research fellow at the University of Canberra’s Center for Conservation and Genomics. “Working on cryopreservation protocols can be difficult and expensive, so alternatives, especially those that are less expensive and more effective, are very welcome,” added Clolo, who was not involved in the study.

In the study, the scientists stored the lyophilized cells at minus 30 degrees Celsius, but they previously discovered that the lyophilized mouse spermatozoa can survive for at least a year at room temperature, and they believe that somatic cells will react in the same way. Wakayama said the technology could “eventually enable the storage of genetic resources from around the world at a lower cost and with greater security.”

This work is an extension of the years of research into cloning and freeze-drying techniques undertaken by Wakayama and colleagues. One of their most recent studies involved freeze-dried mouse sperm sent to the International Space Station. The cells were successfully rehydrated after returning to Earth despite being in space for six years, and produced healthy baby mice.

France 24/AFP

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