An acronym for “Clustered Regularly Interspaced Short Palindromic Repeats,” CRISPR gene editing has made headlines around the globe for more than a decade. This revolutionary laboratory technique gives scientists the ability to remove and replace strands of DNA with unprecedented precision and ease.
The latest news in the word of CRISPR gene editing comes out of Kyoto University in Japan, where a team of researchers led by Dr. Yu Shirai has broken important new ground in the development of gene-editing on insects. As reported in the Vice Magazine article “Scientists Use Gene Editing to Create Mutant Cockroaches in Breakthrough,” this research team recently successfully edited the genes of cockroaches using CRISPR-Cas9.
CRISPR-Cas9 is an advanced gene editing approach that strategically employs an enzyme called Cas9. This enzyme allows researchers to wield a tool that acts much like a highly exact pair of molecular scissors, cutting and inserting DNA strands to develop new treatment options for serious diseases or accomplish a wide range of highly desirable ends.
In May of 2022, Dr. Yu Shirai and his team of researchers announced that they had produced the world’s first “knockout cockroaches” by enhancing them with artificially inactivated genes that they passed on to their offspring. Researchers injected genetic materials into mature female cockroaches of the species Blattella germanica, introducing altered genes for eye color. When these females gave birth, the research team found that up to 21.8 percent of their children inherited the artificial eye color mutation. The team’s final study report concluded that the 21.8 percent figure represented the first establishment of a knockout cockroach line.
While previous studies have successfully edited the genes of insects by microinjecting CRISPR materials into embryos, this technique has been unavailable for use with many insect species due to the inaccessibility of their embryos. Cockroaches are one of those insects, as the female cockroach body will shield fertilized eggs in extremely hard cases for days if not weeks as the offspring prepares to hatch.
By introducing CRISPR materials directly into mature females, Dr. Yu Shirai’s Kyoto University research team was able to use a “direct parental’’ approach to prove that gene editing can be used to create “mutant” cockroach offspring capable of passing their mutations from generation to generation.
The team’s findings were even more impressive when they applied the same CRISPR gene editing technique to the red flour beetle (Tribolium castaneum). In this case, the study produced knockout beetle offspring that retained the inherited mutant gene at a rate of 50 percent.
The groundbreaking results of the Kyoto team’s cockroach and beetle studies carry tremendous promise for a variety of reasons. As a taxonomic class, Insecta contains more than a million different species, representing what the Kyoto team calls a treasure trove of diversity with a vast potential to answer foundational scientific questions that have eluded biologists for centuries. By establishing knockout lines of both cockroaches and beetles, the team has created a blueprint for future research that will focus on other insect species. This new avenue of insect study is likely to provide a much more comprehensive view of biological evolution as a whole.
Beyond revealing the complicated evolutionary backstories of insect species, CRISPR gene editing can help human beings manage specific insect populations in the present and into the future. Pest control is just one example of a promising application of gene editing in insects. By introducing certain permanent characteristics into insects through strategic gene mutation, experts may gain a nearly endless capability to limit their numbers or alter their environmental effects.