By: Catherine Buren
Human genetic modification is the direct manipulation of the genome using molecular engineering techniques, according to the Center for Genetics and Society. Recently developed techniques for modifying genes are often called “gene editing”, and people have been paying scientists for the purpose of changing the genes of their babies to ensure their health. The term “designer babies” has been coined and there are arguments over the justness and ethics of the trend. Is genetic engineering in humans ethical? Ask anyone but the scientists who are changing the appearance of the future human race.
Scientists are exploring a new technique, prime editing, that is more precise and uses certain naturally occurring enzymes, including reverse transcriptase, to edit DNA. (Source: Evan Oto/Science Source)
The Background
Scientists have discovered a new DNA editing technique that aims to simplify the process of rewriting human genetic code precisely and safely. DNA and RNA are both types of nucleic acids. DNA contains genetic information, and RNA transports that information to make proteins. The technique entails the fusion of two enzymes: CAS9, an enzyme previously used in CRISPR, and another called reverse transcriptase, an enzyme that catalyzes the formation of DNA from an RNA template in reverse transcription. According to the Center for Genetics and Society, “the combined enzymes are coupled with a molecule involved in decoding DNA known as RNA. In this case, the RNA, called pegRNA, is engineered to direct the editing enzymes to the target site in the DNA being edited and carries the new edited sequence.” {1} Although scientists are excited about this promising new find, they also worry about the implications of the technique for the genetic alteration of babies before they are born, as this poses many health risks for the newborn.
The Research
One advantage of the new editing style is that, unlike the previously used CRISPR technology, “prime editing” does not require the cell to be able to divide in order to make the programmed changes in DNA. Thus, prime editing could be used to correct genetic mutations in nondividing cells, such as those found in the nervous system. Many diseases are caused by mutations in genes in such nervous system cells, such as Parkinson's and Huntington's diseases. The genetic modification required to correct these mutations would change the genes in eggs, sperm, or early embryos. Commonly known as “inheritable genetic modification” or “gene editing for reproduction,” these alterations would “appear in every cell of the person who developed from that gamete or embryo, and also in all subsequent generations” {2}. Genetic alteration is a continuously expanding field and it must be controlled and regulated in order to save the lives of those who are our future {1}.
Sources:
{1} Stein, Rob. “Scientists Create New, More Powerful Technique To Edit Genes.” NPR, NPR, 21 Oct. 2019, https://www.npr.org/sections/health-
shots/2019/10/21/771266879/scientists-create-new-more-powerful-technique-to-edit-genes.
{2} CGS. “Human Genetic Modification.” Human Genetic Modification, Center
for Genetics and Society, https://www.geneticsandsociety.org/topics/ human-genetic-modification.