Scientists Make Mouse Clones From Freeze-Dried Cells in a Cloning Breakthrough

It is a much safer and more cost-effective method.

Animal extinction is occurring at an alarming rate as a result of human activities, including direct killing and habitat damage. Cloning is one of the activities at the forefront of this since many have reached a stage where conservation and breeding efforts are the only way to preserve the species alive.

But doing so is costly and prone to failure. The genetic material is kept at extremely low temperatures, and if there is a power outage or the freezers become tainted in any way, it is destroyed. It also depends on the successful extraction of healthy sperm, which is not a simple or enjoyable process.

The capacity to clone mice using just somatic cells (not sperm or egg cells) that have been freeze-dried, a method substantially more suited to the task, has now been proved by recent study. The results were described in a report that appeared in Nature.

Here, the scientists demonstrate that freeze-dried somatic cells may result in healthy, viable clones, indicating that this method may be crucial for the development of substitute, less expensive, and riskier liquid nitrogen-free biobanking options.

The removal of sperm or eggs, such as those from the last Northern White Rhino, and long-term preservation of sperm and embryos until they can be put into a female, are current cloning procedures.

In order to build on this, Teruhiko Wakayama and associates from the University of Yamanashi used freeze-dried somatic cells to supply the genetic material required for cloning. The researchers took a sample of mouse somatic cells and used a process called freeze-drying, in which the material is frozen before the ice is removed. The sample can be frozen in this way for up to nine months.

The technique causes the cells to decompose, but the scientists were able to execute somatic cell nuclear transfer and save the nucleus, which has all the genetic material required to produce an early blastocyst. The scientists soon succeeded in developing stable embryonic lines from the frozen material.

The mice were implanted into females and then produced healthy cloned litters, which were mated to show they could breed.

The research is a significant step toward effective cloning, although it has certain shortcomings. Compared to conventional techniques, freeze-drying causes greater DNA damage, and somatic cell cloning has a somewhat higher risk of birth abnormalities. Before it may be used as a way to conserve vulnerable species, these problems must be resolved.