Gene Editing Makes Cats Glow in the Dark

Gene editing is a prominent technology in the world of modern science, and advances in gene editing technology allow scientists to genetically modify living organisms. Typically using CRISPR, or CRISPR-Cas9, scientists modify an organism’s gene—like making a cat glow in the dark—to improve the organism’s quality of life while contributing to our current understanding of genetics.

A model of CRISPR on a molecular level

Merlin Crossley, deputy vice-chancellor and professor in molecular biology at the University of New South Wales, explains that CRISPR is like a microscopic pair of scissors that can cut DNA; CRISPR searches through a cell’s DNA for a specific DNA sequence to cut. In order to find the cutting site, a copy of the targeted DNA sequence scientists want to cleave, called guide RNA, is given to CRISPR to read. Once CRISPR reads the DNA sequence, it can look through a cell to locate the same DNA sequence and cut it. This process allows scientists to choose what DNA to cut, which makes CRISPR more efficient and precise than previous technologies. After cleaving, a cell heals its DNA by replacing the lost DNA with other available DNA. If scientists deliver desired DNA (DNA containing a desirable trait) into a cell alongside CRISPR, scientists can remove an undesired trait using CRISPR and have a cell repair the cut with a desired trait simultaneously. CRISPR is most useful in editing single-celled organisms and organisms with a low cell count, like plants, since CRISPR can only edit one cell at a time. Since every cell in an organism’s body shares the same DNA, CRISPR can be used to genetically modify multicellular organisms if the organisms are edited in their early stages, like the embryo stage, when they have a low cell count.

CRISPR has had many uses in contemporary science. An interesting use of the technology is to make cats glow in the dark. Although this practice seems jovial, it actually has a very practical use in genetics. Reviewing the success of a gene editing trial can be difficult and involved since the naked eye cannot see the genes change; however, it’s very easy to see when a trial using the bioluminescent gene is successful since the animal will glow in the dark. Knowing this, scientists use the bioluminescent gene to mark the success of editing other genes that the naked eye can’t see. For example, the bioluminescent gene is given to cats alongside a gene that prevents the feline form of AIDS. If the cat glows in the dark, there’s a very high chance that the AIDS prevention gene was also successfully administered to the cat.

CRISPR is a very complex technology, so I hope I explained it well. If you have questions about CRISPR or want to know more, feel free to email me at cromero@nslancers.org.