Despite its promise, will gene editing be used as a legitimate therapeutic tool or as a mere way to manufacture “perfect” designer babies?
By: Ringo Bones
The promise of effectively curing inheritable diseases and the dangers of indiscriminately manufactured designer babies is now a step closer thanks to gene editing – which is an improved version of gene therapy. Techniques to edit human DNA for therapeutic means have been around for some time. One method is gene therapy which was already in regular use for the past 15 years. Gene therapy involves using a disabled virus – known as viral vector – to deliver a synthetic functioning copy of gene into cells. Sadly, this method has a glaring disadvantage because there is no way for scientists to know where the gene will end up amidst the billions of letters of DNA code in the nucleus of cells.
The latest improved method of “gene therapy” dubbed as gene editing or genome editing offers something far more precise – adding the gene in an exact location. And unlike older gene therapy methods, gene editing can also be used to snip out a faulty section of DNA.
There are currently several types of gene editing schemes, but the technology really took off three years ago when a cheap and efficient method was developed by Prof. Jennifer Doudna of University of California, Berkeley and Prof. Emmanuelle Charpentier, now at the Helmholtz Center for infectious Research in Germany. Known as Crispr-Cas9, it has been adopted by scientists around the world.
Crisprs (clustered regularly interspaced short palindromic repeats) are sections of DNA, while Cas9 (crispr-associated protein 9) is an enzyme. They are found in bacteria which they use to disable attacks from viruses. Rather like a GPS sat nav, Crispr scans the genome looking for the right location and then use the Cas9 protein as “molecular scissors” to snip through the DNA. Prof. Doudna and Prof. Charpentier realized that this bacterial cut-and-paste system could be used to edit human genes. Almost immediately Crispr became the gene editing technique of choice because of its speed, accuracy and simplicity. It has caused a quiet revolution in research labs across the world. Experiments which once took months can now be done in weeks and the potential is vast.
Last month, scientists said they had used it to create a mosquito that can resist malaria. Plant breeders are using Crispr to create disease-resistant strain of crops. Back in April 2015, researchers in Mainland China edited human embryos to try to correct a faulty gene that caused an inherited blood disorder. The embryos used were never destined to be implanted, but the research rang alarm bells about the implications of gene editing – i.e. the “specter” of perfect blond blue-eyed designer babies and editing out mental disorders like manic depression, which unfortunately, is a prerequisite mental disorder for brilliant poets, authors, musicians and playwrights.