Virgin mouse gives birth after gene-editing experiment: scientists


Virgin mouse gives birth after gene-editing experiment: scientists

A virgin mouse has given birth to babies that were conceived from an unfertilized egg, as part of a groundbreaking new study.

The experiment, which was conducted by researchers at Shanghai Jiao Tong University, was published on Monday in the Proceedings of the National Academy of Sciences.

The researchers promoted asexual reproduction in the mouse by altering the DNA in 200 unfertilized eggs.

The researchers altered genetic markers which require a genome from a second parent.

The process bypassed the requirements of a sperm cell for reproduction and allowed an egg to grow into an embryo by replicating its own cells.

Around 190 of those embryos were transferred into surrogate mother mice.

The results led to an “immaculate conception” of a litter of mice pups that were genetically-identical clones of their mother.

But of the 190 implanted eggs, only three pups ended up being born, and just one survived.

The research was into parthenogenesis – which is the spontaneous formation of an embryo from an unfertilized egg cell.

Parthenogenesis is not uncommon in the animal world, especially in invertebrates like worms.

Mice scurry around stored grain on a farm near Tottenham, Australia.The researchers promoted asexual reproduction in the mouse by altering the DNA in 200 unfertilized eggs.AP/Rick Rycroft

But it is very rare in mammals because of genomic imprinting.

When genes undergo imprinting, they often get stamped with an identifier that indicates the parent of origin during the formation of egg and sperm cells.

This genetic stamping plays a pivotal role in the development of an organism and influences which parental genetics are passed down from the mother and father.

In this study, researchers looked at these marked genes in mice and used a gene-editing method known as DNA methylation to see if they could “improve parthenogenetic development.”

The researchers said that using DNA methylation allowed them to essentially “rewrite” seven imprinting control regions (ICRs), resulting in an immaculate conception.

“By the targeted methylation editing of seven ICRs, we were able to generate viable full-term offspring directly from single unfertilized mouse oocytes,” the study’s authors wrote.

The team used CRISPR, a gene-editing tool, to remove the genetic marks on 220 unfertilized mouse eggs, of which 190 were successfully transferred to foster female mice, according to a report by The Daily Beast.

From the successful transplants, three mouse pups were born, with only one surviving.

“The transfer of modified parthenogenetic embryos into foster mothers resulted in significantly extended development and finally in the generation of viable full-term offspring,” the study read.

“These data demonstrate that parthenogenesis can be achieved by targeted epigenetic rewriting of multiple critical imprinting control regions,” it continued.

The findings in this research open many avenues in genetics research and medicine that may help us to not only regulate reproduction but to cure genetic diseases.

Scientists are currently exploring genome editing for single-gene disorders such as cystic fibrosis, hemophilia, and sickle cell disease, though many believe it may also hold promise for the treatment and prevention of cancer, heart disease, and HIV.

This story originally appeared on The Sun and has been reproduced here with permission. 

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