Justified ban on genetically-editing human germ line
Under the Microscope
Imagine a world where you could choose the characteristics of your child, from eye or hair color to the degree of his or her intelligence. Many people recognize the moral issues inherent in eugenics, roughly defined as improving the human race through selection for desired characteristics. The potential for genetic discrimination against “imperfect people” would become a real concern. If the procedure were expensive, the gap between the rich and the poor would only increase. And perhaps diversity, one of the qualities that we cherish in our population, would greatly diminish.
For many of us, this scenario seems like something out of a standard-issue science-fiction film — something that might be possible tomorrow but most definitely not today. However, with new gene-editing technologies, no longer is this an issue of the past, that fictional scenario now has the potential to become a reality. It is now possible, with today’s technology, to create a genetically perfect race. What a creepy thought, huh?
So it is of no surprise that a few weeks ago, when rumors began to spread about scientists attempting to try a new gene-editing technology on human embryos, scientists from the International Society for Stem Cell Research called for a moratorium on using gene-editing techniques to alter the human germ line (the sperm and egg cells that carry genetic information from one generation to the next).
Genetic modifications to somatic cells, or body cells other than sperm or egg cells, have been utilized for several years to cure some genetic diseases, such as HIV/AIDS, hemophilia, sickle-cell anemia and certain cancers. Through this process of gene therapy some somatic cells are extracted from a patient, genetically engineered and then placed back into the patient’s body. The idea is that the procedure will “fix” enough somatic cells, that when those cells divide and spread the healthy genetic code, the patient will consequently be cured of the genetic disease.
In 2012, scientists from the University of California, Berkeley developed an efficient gene-editing technology, known as CRISPR-Cas9, which has made gene therapy procedures easier to carry out. The technology works by using RNA that recognize specific sequences of DNA and then mutating the DNA at those precise locations. Not only is the technology fairly easy to use, but it is also allows researchers to edit genes in ways that were impossible prior to the advent of CRISPR-Cas9.
In fact, the technology is so efficient that it has become easier than ever for scientists to cause mutations in germ line cells — mutations that could be helpful in eradicating genetic diseases. Such mutations could “fix” one patient’s germ cells, and thus, all the patient’s children would have that “fixed” gene as well — the technology has the potential to cure genetic diseases across multiple generations.
Still, there are practical and ethical concerns to altering germ cells. For one, the procedure is not one hundred percent accurate, and the long-term effects are unknown. Sometimes the CRISPR-Cas9 technology targets sequences of DNA that lie outside the intended target gene sequence and undesired mutations result. Not enough research has been done to determine what the effects the procedure are over multiple generations. The lack of data and unknown future effects prove that informed consent to potential patients undergoing germ-line therapy would be difficult to provide. Many scientists also worry that if we begin experimenting on human germ cells, complications could arise that could compromise research funding in gene therapy fields. In essence, prematurely using this new technology before standards and regulations are in place could put an end to research that aims to discover new cures to genetic diseases.
Some have pointed out that genetic modifications that affect multiple generations have already been approved by the United Kingdom, which approved using in-vitro fertilization (IVF) procedures to produce three-parent babies a few months ago. In this procedure, which aims to cure mitochondrial disease, the embryo’s genetically faulty mitochondria are replaced by genetically healthy mitochondria. Because these new mitochondria can be passed on to future generations, this procedure can be viewed as a genetic alteration to the germ line. Perhaps this IVF procedure is seen as a more ethically acceptable procedure than using the CRISPR-Cas9 technology because the IVF is limited to mitochondrial DNA, which contains very few genes, and because the IVF cannot target specific sequences of DNA.
Nevertheless, this slim distinction begs the question of where to draw the line in regards to altering the human germ line. By what means is it ethical to cure genetic disease? And what constitutes a genetic disease anyway? Until a strong line between the moral and immoral is established by legal regulations, I believe that the scientists had the right idea in putting a temporary halt to germ-line modifications using CRISPR-Cas9.
Vandana Apte is a School of Environmental and Biological Sciences sophomore majoring in biotechnology with a minor in public health. Her column, “Under the Microscope,” runs monthly on Thursdays.