14 March 2022
A team of researchers from China and the U.S. have managed to obtain offspring from a single unfertilized egg from a mouse. The research was published in the journal PNAS and reveals that a type of reproduction, thought to be impossible in mammals, can be achieved using genetic manipulation techniques. According to the authors, the advance may lead to novel applications in agriculture, research, and medicine.
Mouse pups 🐭 born from unfertilised eggs using #CRISPR editing ability🖌️. It would be the first mammal to achieve asexual reproduction (parthenogenesis, a process without fertilization), what opens many opportunities in agriculture🍅and medicine💉.👇https://t.co/tSp2m4Q7qx
— Núria Vázquez Bellón 👩🔬 (@nuriavazquezbe) March 13, 2022
A team of researchers affiliated with several institutions in China and one in the U.S. has successfully derived offspring from a single unfertilized mammalian egg—in a mouse. In their paper published in Proceedings of the National Academy of Sciences, the group describes their technique when tested in mice.
Parthenogenesis is the development of embryos from a single unfertilized egg. In nature, it occurs in aphids, fish, reptiles, scorpions, mites and some bees—but not in mammals. In mammals, sexual reproduction involves a fusion of male DNA with female DNA, with the resulting offspring having genetic material from both parents. Prior research has shown that most of the cells in mammals express copies of genes from both parents—but a few do not, instead expressing genes from only the mother or the father. In their work, the researchers took advantage of such exceptions.
— Phys.org (@physorg_com) March 8, 2022
The Independent explains that “until now, artificially creating this form of reproduction in mammals has not been successful mainly due to a process called genomic imprinting in which some genes are chemically tagged to indicate their parent of origin”.
In the new study, scientists have showed that parthenogenesis is possible in mammals through a new targeted genetic manipulation technique using the gene-editing tool CRISPR, which are chemical modifications that can alter gene activity without changing the underlying DNA sequence.
As the researchers note, previous attempts to impose parthenogenesis in mammals failed due to genetic imprinting. The researchers got around this problem using a different approach. First, they took an egg from a mouse, and then, using CRISPR (a genome-editing system), they altered the genes to mimic those that the male parent would have passed on during natural fertilization. Then, an enzyme was injected into the female gamete, which activated some genes to make the genes in the egg similar to those fertilized by the father.
The Daily Mail points out that “only one live offspring survived to adulthood, highlighting the need for additional research and refinement of the technique used in an effort to improve its success rate. Nevertheless, the results suggest that parthenogenesis can be achieved in mammals through the chemical DNA changes used by the scientists.”
CRISPR: What is the future of gene editing? | Start Here
How Researchers Made Mice Pups from Two Moms and Two Dads | SciShow News
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