CRISPR / Cas9 is a form of genetic editing that holds a lot of promise, such as the killing of cancer cells, but also comes with some hefty warnings that could cause DNA damage. So far, scientists have been using CRISPR / Cas9 in a variety of plants and animals to edit genetic information, including attempts to practice what is called "active genetics."
This last approach is an attempt to edit the genome that controls which of the two copies of a gene is passed to the next generation. But the technique is complicated and rife with obstacles so so far used only on insects.
A team of biologists has now achieved the world's first CRISPR / Cas9-based approach to controlling genetic inheritance in a mammal
"Our motivation was to develop this as a tool for laboratory researchers to control the inheritance of multiple genes in mice, "said lead assistant professor at University of California San Diego Kimberly Cooper. "With further development we think it will be possible to make animal models of complex human genetic diseases such as arthritis and cancer that are not currently possible."
To achieve their lofty goals, researchers engineered an active genetic "CopyCat" DNA element in the gene responsible for the fur color in the mouse and successfully succeeded in controlling the mouse fur color, making it white instead of black. Then, over a two-year period, they expanded their work to successfully determine that the CopyCat element could be copied from one chromosome to the other in order to repair the DNA target by CRISPR / Cas9
As a result , they found that as much as 86 percent of the mice offspring inherited the CopyCat element from the female parent. This is a great improvement on the usual 50 percent naturally achieved.
According to UC San Diego Professor Ethan Bier, a coauthor study, the results, "open the way for various applications in synthetic biology including modular assembly of complex genetic systems for the study of various biological processes. "
Cooper and her team are working to build on this first active mammalian genetic gene by extending it to multiple genes instead of the single gene alteration possible now
"We have shown that we can convert one genotype from heterozygous to homozygous." If this can be implemented for multiple genes at once, it could revolutionize the mouse genetics, "said Cooper.
The work could lead to a significant reduction in the time and cost needed to advance biomedical research on human diseases. But for Cooper and her team, it goes beyond that. Her research is also a way of exploring evolution itself.
"We are also interested in understanding the mechanisms of evolution," said Cooper. "For certain traits that have evolved over several thousands of years, the number of genetic changes is greater than we can currently assemble in the mouse to understand what caused bat fingers to grow into a wing, for example. these functional genetic tools to understand the origins of mammalian diversity. "
The study is published in the Journal Nature