SIX-LEGGED MOUSE: an accidentally created lab monster led to a ground-breaking discovery
Photo by Taton Moïse on Unsplash
We’re familiar with the idea that all mammals have four limbs. Only insects and crustaceans have more. However, modern genetic experiments have recently begun to make serious adjustments to nature’s design.
Why scientists are doing such strange things at first glance is described in an article in the journal Nature Communications, devoted to one of the significant scientific breakthroughs in the field of genetics, which was made entirely by accident.
LEGS INSTEAD OF GENITALS
There’s hardly any need to remind you that under natural conditions, a typical mouse embryo has only four legs. However, in the skillful hands of Portuguese biologist Moisés Mallo of the Gulbenkian Science Institute in Oeiras and his colleagues, the mouse embryo was transformed into a six-legged animal.
Two additional limbs appeared in the rodent in the abdominal region, in the genital area. This happened after the embryo, at a certain point, was switched off the corresponding gene, which was not given about half to develop.
Thus, with the help of genetic engineering, scientists wanted to understand what effect changes in the three-dimensional structure of DNA have on embryo development.
WANTED TO STUDY THE SPINAL CORD
At the center of scientific interest of Portuguese biologists was the protein Tgfbr1. This is a receptor protein that has a significant impact on various aspects of embryonic development. By artificially interrupting the formation of this protein, the researchers wanted to trace what happens after that to the mouse organism.
In particular, with its spinal cord. However, things did not go as the scientists expected. The article in Nature says nothing about what the geneticists learned about the connection of the protein mentioned above with the formation of the spinal cord. However, it describes in detail the side effects of the experiment, which the researchers did not expect at all.
A DISCOVERY THAT FOUND THE SCIENTISTS
When one of Moises Mallo’s graduate students came to check on the test mice, she was surprised to find that they had two extra legs in place of genitals. Since none of the experimenters had expected such a result, the graduate student immediately rushed to Mallo to tell him about the «miracle» that had happened.
The scientist was no less surprised than his colleague. Speaking to journalists and the scientific community, he admitted that he did not choose this project; on the contrary, the project itself chose him. Chance directed Mallo’s research along a completely unexpected, different path from the one he had initially intended.
A PROTEIN THAT MAKES MIRACLES
But it wasn’t the extra legs that surprised scientists. Science was previously aware of the fact that the vast majority of four-legged animals have genitals and hind legs growing from a common «point». The penis, clitoris, and the two legs develop from the same primordial structures. However, the role of the Tgfbr1 protein in this process has never been understood. As a matter of fact, this is the essence of the discovery of Mallo and his team.
As a result of further research into the phenomenon of six-legged mice, they found that Tgfbr1 changes the way DNA is folded in cells in a certain way. It directs these structures and «decides» whether they should be genitalia or legs.
Mallo’s group stumbled upon this phenomenon by accident by deactivating the protein, finding two additional limbs in place of the missing external genitalia.
A PROTEIN THAT MAKES MIRACLES
But it wasn’t the extra legs that surprised scientists. Science was previously aware of the fact that the vast majority of four-legged animals have genitals and hind legs growing from a common «point». The penis, clitoris, and the two legs develop from the same primordial structures. However, the role of the Tgfbr1 protein in this process has never been understood. As a matter of fact, this is the essence of the discovery of Mallo and his team.
As a result of further research into the phenomenon of six-legged mice, they found that Tgfbr1 changes the way DNA is folded in cells in a certain way. It directs these structures and «decides» whether they should be genitalia or legs.
Mallo’s group stumbled upon this phenomenon by accident by deactivating the protein, finding two additional limbs in place of the missing external genitalia.
Original research: Scientists made a six-legged mouse embryo — here’s why