What just happened?
Last week the Royal Swedish Academy of Sciences awarded the Nobel Prize in Chemistry 2020 to Emmanuelle Charpentier of the Max Planck Unit for the Science of Pathogens, Berlin, Germany and Jennifer A. Doudna of the University of California, Berkeley, for the development of a method for genome editing. According to the Nobel committee:
Emmanuelle Charpentier and Jennifer A. Doudna have discovered one of gene technologys sharpest tools: the CRISPR/Cas9 genetic scissors. Using these, researchers can change the DNA of animals, plants and microorganisms with extremely high precision. This technology has had a revolutionary impact on the life sciences, is contributing to new cancer therapies and may make the dream of curing inherited diseases come true.
Although still largely unknown by the general public, CRISPR/Cas9 has the potential to be one of the most influential technologies developed in the 21st century.
What is CRISPR/Cas9 genetic scissors?
CRISPR/Cas9 genetic scissors (hereafter, CRISPR) is a technology that enables geneticists and medical researchers to edit the genome of plants, animals, and humans.
Genome editing (or gene editing) is a form of genome engineering in which DNA is inserted, replaced, or removed from the genetic material of a cell using artificially engineered enzymes, or “molecular scissors.” Germline editing is when this procedure is used on the genome of germline cells. (See below for explanations of these terms.)
The simplistic explanation is that the molecular scissorsCas9, an RNA-guided DNA enzymecuts an enzyme on a specific spot of DNA in the nucleus of a cell. The cell then repairs the break using a piece of single-stranded DNA that has been injected into the cell by scientists.
The following video provides a more in-depth, technical explanation of how CRISPR and Cas9 edit genes.
What is a genome?
A genome is an organisms complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism. In humans, a copy of the entire genomemore than 3 billion DNA base pairsis contained in all cells that have a nucleus.
What is a human germline?
Our genes, the basic physical and functional unit of heredity, are passed on from generation to generation through our sex cells (i.e., ovum [egg] and sperm). These sex cells are part of the germline. The term germline can refer to these cells in an individual or to the lineage of cells spanning generations of individuals. The other cells in the body that are not part of the germ line (and hence do not pass on traits to other generations of people) are called somatic cells.
What is genome editing used for?
According to the National Human Genome Research Institute (NHGRI), genome editing is currently being applied to research on cancer, mental health, rare diseases, and many other disease areas. The CRISPR/Cas9 method has also been used for such purposes as editing genes in crop plants to improve and increase food production, and on laboratory animals to mimic human diseases so they can be studied to test new therapies.
CRISPR may also be used to treat diseases that have genetic bases, ranging from asthma to cancer. Through the application of genome editing technologies, the NHGRI says, physicians might eventually be able to prescribe targeted gene therapy to make corrections to patient genomes and prevent, stop, or reverse disease.
However, such germline therapies raise ethical concerns because changes made on the genome affect future generations. There is also the possibility that germline therapies would pave the way for genetic enhancement, the use of genome editing to change non-medically relevant characteristics, such as athletic ability or height, or to create designer babies.
Is genome editing ethical?
The main ethical consideration for genome editing is the purpose, whether for therapy or enhancement, and the long-term effect on future generations of humanity. This is why the ethical issues differ for genome editing on somatic cells, which are non-reproductive cells and would affect only the individual being treated, and on germline cells, which are reproductive cells that could potentially affect not only the individual but also their offspring and future generations of their descendants.
The concern for germline editing is that therapeutic treatments passed along to future generations may have unexpected and unintended consequences. In essence, we would be experimenting on future generations without their consent.
The other worry is that the procedure could eventually be adopted for non-therapeutic genetic enhancement, a form of eugenics. The process could be used by wealthy people to create designer babies whose genetic improvements (e.g., height, intelligence, longevity) would be passed along to future generations.
From a Christian perspective, therapy implies fixing a malady that results from sin entering the world, such as curing diseases or restoring broken physical systems. Enhancement, in contrast, is attempting to make improvements of the body that are either not the result of sin or not necessarily caused by human brokenness. Distinguishing between therapy and enhancement is a perennially tricky issue for Christian ethicists. Additionally, not all therapy is beneficial, and not all enhancements are sinful.
Using genome editing for enhancement, though, is troubling for several reasons. For example, using the process on ourselves implies that humans know how to improve on Gods general design for the human body. It also can imply that certain traits (such as height or a particular IQ) are so preferable that they should be purposefully engineered so that they can be distributed in a way that is outside the normal distribution range for the human species.
Other concerns include questions about the cultural and social effects of having certain humans be engineered to have the right traits. Will the changes lead to unjust forms of inequality? Will those who do not possess the preferred traits be treated as inferior or sub-human? Will discrimination increase for those who are unable or unwilling to modify their children?
Ultimately, we should oppose non-therapeutic germline editing because children (and future generations of children) are to be considered as gift from God (Ps. 127:3) and not as products that we can tinker with and modify to our preferences.