Dr. Joel Reynolds, a postdoctoral fellow at The Hastings Center recently wrote a very poignant essay in Time magazine arguing that our increasing ability to edit our own genetic code risks eventually eliminating the very genetic code that results in people like his younger brother Jason, who was born with muscle-eye-brain disease, resulting in muscular dystrophy, hydrocephalus, cerebral palsy, severe nearsightedness and intellectual disability. In answering his question – “What, precisely, are we editing for?” – he makes the case that editing the code that resulted in Jason effectively eliminates Jason. I encourage you to read the short article, as any further summary on my part does not do it justice.
How much change of my genetic code would alter my identity? This is an important ethical question as scientists seek to use our growing genetic knowledge to alter our genetic code. Using preimplantation genetic diagnosis (PGD) to eliminate diseased segments of genetic code also eliminates the rest of the genome since a completely disease-free human embryo is selected for implantation and the disease-carrying embryo is destroyed/killed. Obviously, the identity of the implanted embryo is completely different from the destroyed embryo. No identity preservation here.
CRISPR-Cas9 (CRISPR) is held out as the beginning of future techniques to successfully remove and replace sections of our human genetic code. Diseases that are caused by point mutations would seem to be ideal challenges for CRISPR, where removing a single nucleotide effectively cures the individual of the disease, and, at least on cursory consideration, leaves the identity of the individual intact (after all, we would only be changing one nucleotide in the individual’s 3.2 billion nucleotide sequence in their unique genetic code).
Color blindness is one such example, one that I “suffer” from. If my parents had the ability to change my genetic code just after conception to eliminate my color blindness, it seems that I would be the same man I am today, absent the need to have my wife select my ties and socks. However, other life experiences could have been available were my color vision intact, such as F-14 fighter pilot and/or completion of the NASA astronaut selection program, both requiring normal color vision. Likely, I would have been someone with the same identity but certainly with very different life experiences.
At the more serious end of diseases with point mutations is Tay-Sachs disease, where a defective enzyme fails to prevent the build up of toxic fatty deposits in the brain and spinal cord, and, in the infantile form, results in mental impairment, severe sensory pain and pre-mature death. If I had the infantile form of Tay-Sachs disease and my parents changed my genetic code, is my identity different? Am I just the same “me” experiencing a tremendously different life experience or am I a different “me”? If I am a different “me”, is it just because we hold cognitive ability/behavior/function critical to one’s identity? One can lose the function of the nerves in one’s leg and not consider this a challenge to one’s identity. Sustain an injury to one’s brain and the challenge to one’s identity is stronger. Dr Reynold’s makes a similar case in describing his brother Jason as he actually was, compared to how he could have been had the prayers for healing been answered or genetic editing been available. To paraphrase, a “corrected” Jason is no longer Jason.
None of the forgoing discussion considers the human soul as it relates to identity or whether alterations in the human genome affects the human soul (or vice versa?). Those issues will have to wait for another blog post. For now my question is this: How much of my genetic code can I change and still be me?