30 November 2018
To Modify the Human Genome, or Not to Modify the Human Genome
New genetic technologies allow scientists to edit human genes or delete mutant ones and replace them with a healthy one; this may enable doctors to dispel disease genes. Sounds like science fiction right? These gene-editing technologies are real and one of the more efficient technologies is called CRISPR (clustered regularly interspaced short palindromic repeats). This allows scientists to edit the genome by simply, “Cutting out one gene and replacing it with another” (Adams p. 531). This technology is now attainable by scientists and doctors around the world. Due to the simplicity, precision, and high-speed compared to other technologies, several scientists fear it is just a matter of time before someone uses the technology for further unrestricted modifications of the human genome. Although some scientists believe in banishing human disease with technology, others believe it is unethical.
The first time scientists edited DNA in human embryos was in May of 2015. In this attempt, Chinese researchers edited the gene that causes a blood disorder, beta thalassemia. This reduces the production of hemoglobin that can then lead to a lack of oxygen in many parts of the body. At the time this research was considered “off limits” and called “unsafe and premature.” Of the 86 embryos edited, only 28 were successful. This led the researchers to believe that their data supported notions that clinical application of CRISPR is premature at that stage. In December of 2015, a group of international scientists met to discuss germline editing and the decided it would be “irresponsible to proceed” until it could be better approached. This meeting was convened by, “the National Academy of Sciences, the Institute of Medicine, the Chinese Academy of Sciences and the Royal Society of London” (Ladika p.763). In spite of the concerns of the government and several scientists, in 2016 Chinese researchers made “four of 26 embryos resistant to HIV infection” (Ladika p.763). Again, in 2017, these researchers corrected mutations in three embryos. One of these embryos corrected a mutation for the blood disorder previously stated: beta thalassemia, and the other two embryos had a mutation that could eliminate red blood cells.
CRISPR has been used in mouse genetics and researchers have found there are limitations. One limitation is since the scope of the DNA repair system is not to integrate DNA fragments in the genome, “targeted alleles often carry additional modifications, such as deletions, partial or multiple integrations of the targeting vector, and even duplications.”(Flora and Welcker). Another limitation “observed in founder mice generated using the CRISPR/Cas9 approach makes the identification of unwanted genomic modifications at the target site very challenging” (Flora and Welcker). In mice research, the main limitation is the ex...