Scene: A laboratory setting. A scientist begins constructing a new individual by combining parts from two different humans. A new part from one or two additional people is then added. At some point, an electric shock is administered. The scientist observes the composite for a few moments, looking for signs that it is on its way to becoming an autonomous being. It stirs. It's alive.
If this sounds unsettlingly familiar, it should, but not because it is a replay of Frankenstein. The procedures described, currently under evaluation by the British Human Fertilisation and Embryo Authority (HFEA) for the prevention of "mitochondrial diseases," would carry profoundly negative implications for the future of the human species were they ever implemented, and thus warrant much wider concern than they have attracted up until now. In particular, they will facilitate a new form of eugenics, the improvement of humans by deliberately choosing their inherited traits.
Pathogenic mitochondrial conditions affect an estimated 1 in 5,000 live births. These typically arise from a variety of deleterious mutations of the DNA contained within the mitochondria -- the cell's energy-extracting organelles. Some are extremely severe, leading to deafness, epilepsy, and early dementia. Since essentially all the mitochondrial DNA in a new individual is copied from that of the egg, women who harbor harmful mitochondrial DNA mutations understandably would want to avoid passing them on to their offspring. Whether they therefore have the right to bear biological children by any means necessary, and by doing so act as a vanguard of germline (i.e., inheritable) genetic engineering, is one of the major questions of our time.
The HFEA has launched a "public consultation" to gather views on the ethical and social implications of two novel techniques for mitochondrial replacement that have been proposed by investigators at the University of Newcastle in the U.K. and the Oregon Health and Science University in the U.S. These methods would attempt to prevent the propagation of "unhealthy" mitochondria by producing children from the reproductive cells, and parts thereof, of three or four different individuals.
Apart from these manipulations not being necessary to save the lives or alleviate illness of any existing people (their subjects being prospective people), they are inherently unsafe. Unlike in vitro fertilization (IVF) which generates embryos from the biological components that evolved to serve this function, the two methods under consideration by the HFEA de- and reconstruct the fertilized egg in radical ways, unprecedented in the history of life.
One of the methods, pronuclear transfer (PNT), consists of performing in vitro fertilization of an affected egg, removing the egg and sperm "pronuclei" before they have fused into a single "zygotic" (definitive embryo) nucleus, and transferring them with an electric pulse into the fertilized egg of a second woman with unaffected mitochondria which has had its own pronuclei removed and discarded.
The other method, maternal spindle transfer (MST), involves removing the chromosomes (organized prior to fertilization in a structure called the "spindle") from an egg extracted from a woman with affected mitochondria and a second woman with unaffected mitochondria. The spindle (containing most of the cell's DNA) of the first woman's egg would be transferred to the second woman's spindle-free egg, which is then fertilized.
In either case, the resulting tri-parental embryo is transferred to the uterus of the intended mother (usually the female pronucleus or spindle donor) or another woman, where it can be gestated to term to produce a child free of inherited mitochondrial disorders. The advocates of these procedures argue for their alleged low risk by reference to the small amount of DNA involved in the transfer (mitochondrial DNA contains only 37 genes of the estimated 20,000 in the human genome). But the quantitatively small genetic impact is only applicable when the viewpoint of a pronucleus or spindle donor is considered. From the viewpoint of the new individual assembled from these parts and his or her descendents, these methods constitute full-scale germline genetic engineering.
Skepticism that these highly intrusive manipulations, bringing together fragments of damaged cells and embryos, could generate a healthy individual, arises from the implausibility that such concoctions have ever been encountered in the course of animal evolution. Cells have evolved sophisticated ways of repairing aberrant conditions such as DNA or protein damage, but these have been common hazards for all organisms throughout the history of life. Sometimes programmed death -- cell or embryo "suicide" -- is the way out of untenable foul-ups, but this escape route may be thwarted in PNT and MST.
The described techniques also evade protective measures against "heteroplasmy," the mixture of mitochondrial genomes that occasionally results from the persistence of the sperm mitochondrion after fertilization. Ancestral animals that lacked such suppressive mechanisms did not contribute significantly to present-day populations, and recent evidence indicates that heteroplasmy has deleterious effects even when both types of mitochondria are healthy (which is not the case in the replacement protocols). Any humans that came to term and to maturity as products of these procedures would represent uncontrolled laboratory experiments.
Given these problems, then, why would a U.K. governmental agency waste time exploring the ramifications of these techniques? (Things are different in the U.S., where the lack of any consistent regulations concerning reproductive technologies permitted the production of three-parent children using a more primitive technique than the two outlined above, which, problematically, resulted in both a high frequency of heteroplasmy and chromosomal anomalies.)
One factor in placing these procedures on the social agenda seems to be the conflation of biological modification of people who do not yet exist with medical treatment of actual sick people. The attempt to improve future people is not medicine, however, but a new form of eugenics. In its willingness to risk producing damaged offspring by modifying embryos' genomes, this "correctionist" eugenics goes even beyond the "selectionist" version of the forced sterilization programs for criminals and others considered biologically inferior in conducted the United States and Europe throughout most of the 20th century (and brought to an extreme in Nazi Germany). Activities that are clearly covered by the Nuremberg Code prohibiting nonconsensual human experimentation are recast by proponents of gene-altering technologies as within the alleged rights of parents to exert proprietary control over the characteristics of their prospective offspring.
It must be emphasized that such hypothetical rights are not at all the same as the inviolable commitment of parents to the health and well-being of their existing children. The genetic design of future offspring, even with the limited objective of making these future children more "normal," will open the door to attempts to pick and choose other characteristics, because definitions of normality will vary, as will access to technology and willingness to take risks with future lives.
The fact that some of the individuals who would sustain harm from attempts at genetic engineering would not have otherwise been born is often used as a trump card to justify pursuing the technology despite its hazards. This is a specious argument that could support virtually any kind of embryo manipulation. It also ignores the fact that the social harms of eugenics extend far beyond is effects on individuals. If healthier or "better" children are the objective of these costly interventions, what will be the emergent attitude toward individuals made sicker or "worse" by them, the results of experiments gone awry.
Another factor giving currency to the prospect of genetic engineering is the ambitions of scientists and reproductive physicians with products and services to sell and fame and fortune to be gained. With legal liability for errors committed in the course of voluntary (at least for the donors of the eggs and sperm) experimental procedures like mitochondrial replacement generally lax, the purveyors of the technologies and allied diagnostic procedures feel free to persuade regulatory bodies or hospital boards of the innocuousness of their methods by sophistry such as drawing false analogies between the assembly of embryos from fragments of damaged cells with casting the "genetic dice" in ordinary reproduction.
But perhaps the most insidious factor in calls for acceptance of the idea of genetically engineering humans is the profound misconception of the nature of living organisms that underlies it. Organisms differ from machines or computers by being products of evolution rather than design. But complexity that has accumulated over billions of years does not come with blueprints or instruction books, and cannot be reconfigured with predictable outcomes. Although rejection of the realities of evolution is generally considered to be a sign of scientific ignorance, it unfortunately characterizes the thinking of some professional biologists who are strongly influenced by engineering disciplines.
For example, the bio-entrepreneur Craig Venter has claimed that there is "no difference between digital code and genetic code", and the Stanford University (formerly MIT) "synthetic biologist" Drew Endy asked a New Yorker reporter "What if we could liberate ourselves from the tyranny of evolution by being able to design our own offspring?". This showboating, promoted by think tanks and major media outlets, deceives the general populace by promoting the notion of science as magic, and the scientist not as a cautionary Dr. Frankenstein, but as a valorously adept Harry Potter.
The ironic lesson of the new drive toward DNA-based eugenics (of which the mitochondrial replacement techniques would be the thin end of the wedge), is that despite its being the special initiative of an avowedly progressive sector of biomedicine, it actually brings together some of the most regressive strains of traditional and modern society: valuation of people according to their biological characteristics, parental proprietorship, the marauding entrepreneur and evolution denialism. The HFEA's members may imagine that they are taking cautious steps toward a genetically brighter future, but in actuality they are drawing on darker forces promoting the misuse of technology with clear potential for individual and social harms.
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