This 'strange' mouse has ancient genes older than animal life. Here's how it is different

In a massive breakthrough, scientists created a mouse with the use of ancient genetic tools which are older in comparison to animal life.

The researchers took a gene from single-celled lifeforms and added it to the mouse cells for regenerating stem cells, which were then injected into a developing embryo for creating a living and breathing mouse.

Millions of years ago, before multicellular organisms came into existence, there were single-celled organisms on planet Earth. Some of them, called choanoflagellates, were seen as the animals' closest living relatives.

As per the new research, their genomes have different versions of genes Sox and POU, which are known to push stem cells' formation in mammals and, till now, were believed to be exclusive to animals.

These were now found in a single-celled organism and were then used by scientists to reprogram mouse cells.

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“By successfully creating a mouse using molecular tools derived from our single-celled relatives, we’re witnessing an extraordinary continuity of function across nearly a billion years of evolution,” said study author Dr Alex de Mendoza in a statement.

"The study implies that key genes involved in stem cell formation might have originated far earlier than the stem cells themselves, perhaps helping pave the way for the multicellular life we see today," Mendoza said.

Here's how the mouse was created

The choanoflagellate Sox genes were entered into the mouse cell, which replaced the existing Sox2 genes, and in the process turned the cells into induced pluripotent stem cells (iPSCs).

These cells can develop into any type of cell in the body.

When scientists injected the iPSCs into a mouse embryo, they formed what is called a chimera, which is an animal whose body has cells that are different from each other and contain two different sets of DNA.

The new mouse had traits of both the iPSCs and the donor embryo and had dark eyes and black fur patches, which confirmed that the ancient genes had influenced the development of the animal.

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This is impressive considering the simple origins of the genes. It appears that the early lifeforms had evolved their ways of maintaining pluripotency, much before stem cells and multicellular organisms came into existence.

"Choanoflagellates don’t have stem cells, they’re single-celled organisms, but they have these genes, likely to control basic cellular processes that multicellular animals probably later repurposed for building complex bodies,” Dr de Mendoza said.

The discovery can also help in future advances in regenerative medicine, in which an integral part is played by the stem cells. 

"Studying the ancient roots of these genetic tools lets us innovate with a clearer view of how pluripotency mechanisms can be tweaked or optimised," said co-author Dr Ralf Jauch.

(With inputs from agencies)