Scientists from the United States have presented an alternative to directed gene editing. The recombination of retrons, genetic elements in bacteria, has proven to be a less toxic and faster genetic engineering experiment.
Researchers at Harvard Institute have created a new gene-editing tool that could allow scientists to simultaneously conduct millions of genetic experiments simultaneously. They called this technique retron recombination (RLR), and it uses segments of bacterial DNA that can create fragments of single-stranded DNA.
The scientists noted that CRISPR-Cas9 is probably the best-known technique. Over the past few years, it has made a splash in the world of science by providing researchers with the tool they need to easily edit DNA sequences. It is more accurate and has a wide range of potential applications – with its help researchers can treat various hereditary diseases.
However, this tool has some serious limitations. For example, scientists cannot deliver CRISPR-Cas9 materials in large quantities. In addition, the method can be toxic to cells, since the Cas9 enzyme – molecular “scissors” responsible for cutting DNA strands – often cuts non-target regions.
In turn, retrons can insert a strand of DNA into a replicating cell so that the strand can be incorporated into the DNA of daughter cells. In addition, retron sequences can serve as “barcodes” or “name tags,” allowing scientists to track individuals in a bacterial pool. This means they can be used to edit the genome without damaging native DNA and carry out many experiments at the same time.
Scientists tested retrons on E. coli bacteria and found that 90% of the population turned on the retron sequence after making several changes. They were also able to prove how useful this method can be in large-scale genetic experiments. During the tests, they were able to find antibiotic resistance mutations in E. coli by sequencing the retron barcodes instead of sequencing individual mutants, which greatly accelerated the process.