A possum has become the world’s first genetically modified marsupial . Those responsible for this scientific milestone have been scientists from the RIKEN Center for Biosystem Dynamics Research (BDR) in Kobe, Japan.
CRISPR, now also in marsupials
In laboratory experiments, the experts succeeded in altering a gene responsible for pigments to create albino opossum offspring.
Genetically modified animals, particularly mice and rats, are extremely important tools for investigating biological processes. For example, researchers often silence genes to find out what their usual functions are, and since marsupials have unique characteristics that they do not share with other mammals (such as that their young are born incompletely developed, but develop further in the safety of a pouch such as the kangaroo or suffering from skin cancer through exposure to ultraviolet light), studying them requires developing a representative animal model. To date, the best option is the opossum, which is believed to be the ancestor of all marsupials and whose size and reproductive characteristics are similar to those of mice and rats.
“Marsupials represent one of three existing subclasses of mammals with a number of unique characteristics not shared by other mammals,” said study leader Hiroshi Kiyonari. “Having established the technology in this proof-of-concept experiment, future studies may create genetically engineered marsupials that will impact the fields of mammalian embryology, genomic imprinting, reproduction, neurobiology, immunogenetics, cancer biology, and even comparative evolution “.
For the experiment, the scientists used short-tailed gray possums (Monodelphis domestica), native to South America. They transferred the fertilized egg to the uterus of a fertile female opossum and successfully produced offspring. They applied piezoelectricity, which involves squeezing certain crystals to make electricity flow through them to allow the injection needle for genome editing to penetrate the hard layer and the thick layer that surrounds the fertilized egg (which is surrounded by a hard shell-like structure).
“The piezo has made it possible to inject zygotes [fertilized eggs] without significant damage,” the authors clarify.
Some of the descendants of the experiment were albinos and their genes were inherited by the next generation , marking the first successful gene editing in marsupials.
The researchers say their study will help decipher the genetic background of unique characteristics observed only in marsupials. It could also help in the development of new treatments for diseases that affect humans, such as cancer and Alzheimer’s, according to the team. The ability to modify the genomes of marsupials could help biologists learn more about the animals and use them to study immune responses, developmental biology, and even diseases like melanoma.
Referencia: Targeted gene disruption in a marsupial, Monodelphis domestica, by CRISPR/Cas9 genome editing Current Biology (2021). DOI: 10.1016/j.cub.2021.06.056