The first genetically modified possums were born in the laboratory

The first genetically modified possums were born in the laboratory
The first genetically modified possums were born in the laboratory

Scientists at the RIKEN Biosystem Dynamics Research Center in Japan have created the first genetically modified marsupial. Scientists will now be able to investigate the unique genetic characteristics that are unique to this infraclass of mammals.

For example, marsupials do not develop a full-fledged placenta, and cubs are born prematurely. However, although this is an extremely curious feature of marsupial mammals, they have other characteristics that are of particular interest to researchers.

For example, marsupials, like humans, can develop skin cancer when exposed to ultraviolet radiation.

This is a unique feature not found in other placental mammals besides humans. Scientists are, of course, eager to investigate the genetic traits of marsupials responsible for this human-related weakness.

Also, unlike the young of other mammals, newborn baby marsupials suffering from spinal cord injuries can naturally "heal" themselves.

The underlying genetic processes can be explored through experiments in animal models. So scientists are studying the biological processes of mammals using rats and mice as model animals.

But to create an animal model, it is necessary to obtain genetically modified animals. This is how researchers study the work of genes: by turning off (knocking out) certain sections of DNA, scientists can see what processes in the body they are responsible for.

The researchers chose opossums as an animal model of a marsupial mammal - they are considered the most ancient representatives of marsupials.

In addition, possums are similar to rats and mice in size and in terms of care and breeding. This makes it easier for scientists to conduct experiments - they do not need to create fundamentally new conditions for new animal models.

To edit the genome, it is necessary to inject a special chemical solution into the fertilized egg. The researchers overcame a number of technical challenges to achieve this.

First, opossums have a fairly long estrous cycle (an animal analogue of the menstrual cycle). Scientists injected animals with a hormone that stimulates estrus (estrus): a physiological process necessary for the successful fertilization of an egg.

Second, in order to inject the genome-editing solution into the ovum, a thin needle must be injected. However, fertilized oocytes of opossums are protected by a strong protein membrane that is not easy to pierce with an injection needle.

The scientists used a piezoelectric element along with a needle to make it easier to insert. This method worked.

To illustrate the success of genome editing, the researchers modified a gene that pigments the animal's body. When the work of this gene is disrupted, the pigment ceases to be produced, and the skin of the animal becomes colorless (this genetic trait is called albinism).

Some genetically modified baby possums actually turned out to be albinos and even passed on this genetic trait.

So researchers have successfully demonstrated the first ever method of genetic modification of marsupials.

The authors of the work note that this achievement opens up new opportunities in the field of mammalian embryology, genomic imprinting, reproduction, neurobiology, immunogenetics, cancer biology, and even comparative evolution. SciTechDaily portal reports about it.

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