Genome Editing dates back to the 1950s when the DNA double helix was first discovered. Since then, scientists have been tirelessly working on ways to edit the genome to alter the blueprint of life. Genome editing (also called gene editing or genome engineering) is the addition, deletion, or alteration of the genetic code of an organism.
Gene editing technology uses enzymes called nucleases that are targeted toward a specific site in the genome by a guide sequence or binding domains present within the nuclease itself. Once it identifies and binds to the target DNA, the nuclease can then begin to wield its magical power of editing.
Currently, 3 important gene editing technologies are highly used. They are —
CRISPR-Cas9 technology has been taking the scientific community by storm since its development in 2012. Researchers are widely using CRISPR to modify genomes for a variety of applications, including medical diagnostics, DNA imaging, and therapeutics. CRISPR-Cas9 is far cheaper, quicker, more accurate, and more efficient compared to the other genome editing methods. One of the most exciting applications of CRISPR and CAS gene technology is regenerative medicine. By targeting cells with damaged or missing parts of their genetic code, CRISPR-Cas9 help them initiate repairs or replacement. This is used in cases where organs are damaged due to disease or injury, or to restore loss of organ functioning due to injuries or aging. In 2021, the market for gene editing technology was estimated to be worth USD 4 billion, and by 2031, it is expected to attain more than USD 22 billion.
As genome editing technology evolves, it will be used more and more during routine medical examinations and surgeries. A New Zealand woman received CRISPR gene-editing treatment to lower her cholesterol permanently. The woman had heart disease, with greater susceptibility to high cholesterol. The gene editing technology used for this cholesterol-lowering treatment, developed by Verve Therapeutics, relied on “CRISPR 2.0”, in which a single DNA base was swapped for another. This technology is safe as an important gene is not cut by mistake. “CRISPR 3.0” will take gene editing to a whole new level by allowing scientists to insert blocks of DNA into a genome, which could help them replace disease-causing genes. Human genome editing can expedite the accurate diagnosis of diseases, conduct targeted treatments, and prevent many genetic disorders. Already, somatic gene therapies, are being successfully used to address HIV and sickle-cell diseases. Gene editing is also becoming increasingly popular in preventing diseases by correcting faulty genetic codes before they cause any health problems. For example, scientists have used gene editing to correct defective genes responsible for cystic fibrosis in pigs, so they no longer develop lung infections. They are now experimenting with this technique on humans with CF so they can live their everyday lives without experiencing the symptoms. Many other uses of gene editing are on the cusp of discovery, including in cancer treatment or in reversing age-related damage (like Alzheimer's).
A new gene editing technology called Base Editing was recently used to alter immune cells and treat a teen with leukemia successfully. The 13-year-old Alyssa has been in remission ever since. The edited cells were administered to the patient to identify and destroy T-cells in the body, including leukemic T-cells Base editing is expected to be even more precise than the CRISPR technique in cancer services and has fewer side effects.
This technology has numerous potential applications outside the medical field, including food security and crop improvement. For example, CRISPR-Cas9 is used to develop crops that withstand harsh environmental conditions or reduce their reliance on pesticides or other chemicals. Over 180,000 CRISPR reagents have been distributed to over 4,000 institutions in 87 countries as of 2020, demonstrating the technology's worldwide reach. Researchers successfully demonstrated precision gene editing in the improvement of miscanthus, a perennial crop harvested for sustainable bioenergy production. This genetically complex grass is being used as a significant source of biofuels and renewable bioproducts and in carbon sequestration. Fish Farming is a big industry in the US. But infections claim many fish every year. Genetic engineering of fish with genes such as those of an alligator is being successfully conducted on a large scale to protect them from diseases and cut down on waste, reducing the impact of fish farming on the environment.
The WHO Director-General, Dr. Tedros Adhanom Ghebreyesus said that “Human genome editing has the potential to advance our ability to treat and cure diseases, but the full impact will only be realized if we deploy it for the benefit of all people, instead of fueling more health inequity between and within countries”. Genome editing innovations need to be inclusive of the versatile human population and experiences and not solely limited to the richest strata of societies.
Some issues concerning genome editing technology include-