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Can Human Evolution Be Controlled?

Earlier this month, an international initiative convened by the national science academies of the United States, China, and the United Kingdom released a major report on the implications of new “gene-editing” technologies, most notably the recently developed tool CRISPR/Cas9. The report was broadly optimistic about the scientific and technological potential of tools like CRISPR/Cas9, which has been employed in labs around the world, generated thousands of scientific publications, and attracted over a billion dollars in venture capital for private companies exploring its medical and commercial applications.

These gene-editing techniques may transform our world as profoundly as many of the greatest scientific discoveries and technological innovations of the past — like electricity, synthetic chemistry, and nuclear physics. CRISPR/Cas9 could provide urgent and uncontroversial progress in biomedical science, agriculture, and environmental ecology. Indeed, the power and depth of operation of these new tools is delivering previously unimagined possibilities for reworking or redeploying natural biological processes — some with startling and disquieting implications. Proposals by serious and well-respected scientists include projects of broad ecological engineering, de-extinction of human ancestral species, a biotechnological “cure” for aging, and guided evolution of the human future.

The questions raised by such projects go beyond issues of individual rights and social responsibilities to considerations of the very source and significance of the natural world, its integrated and interdependent processes, and the way these provide the foundational frame for the physical, psychological, and spiritual meaning of human life.

Cures — and Control?
With the CRISPR revolution, researchers are reporting dramatic gene-editing advances in mouse models in a wide range of genetic disorders, including sickle-cell anemia, Duchenne muscular dystrophy, and Fanconi anemia. And an article published in late 2016 in the journal Nature reported that a Chinese group has become the first to treat a human being — a lung-cancer patient — with cells that contain genes edited using the CRISPR/Cas 9 technique.

The dramatic potential of such therapies is immediately obvious; for the first time we will have the power to treat hundreds, perhaps thousands, of diseases and conditions for which we currently have no effective therapy. It is important to recognize that in many cases it may not be necessary to alter all the cells in an organ, just 20 or 30 percent may be adequate to restore natural functioning. It is also obvious that, in certain cases, the earlier the genetic interventions can be made, the better the treatment outcome will be in preventing disease onset and allowing normal development. This has reawakened the long-held hope that we might one day be able to make targeted DNA modifications directly at the level of the human gametes (sperm and egg) or early embryos, and thereby remove a genetic disease once and for all from a family lineage.

But this, in turn, raises challenging questions about what degree of acceptable risk and what types of conditions should count as worthy targets of our interventions. Are albinism and dyslexia conditions we should treat? And what about parental preference for hair and eye color or taller stature? Red hair, for example, is caused by a single gene. Most conditions we would care about — intelligence, beauty, longevity — result from interaction among many genes and would not be easy to target, but as we learn more about the genetic basis of depression, autism, and Parkinson’s disease, we may be tempted to develop preemptive germline interventions.

Harvard geneticist George Church has compiled a list of “rare protective gene variants of large impact” that exist naturally in the human genepool — but only in a few people. These include variants correlated with extra-strong bones; lean muscles; lower risks of coronary artery disease, cancer, and diabetes; and greater resistance to viruses — all of which might improve general health if more common.

In response to such suggestions, developmental biologist Stuart Newman warns:

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.

Remaking Humanity
Yet, some argue that it is human nature and human destiny to improve ourselves even at the most fundamental level of our genes. These include the “transhumanists,” an international intellectual and cultural movement advocating technologically mediated enhancement of human intellectual, physical and psychological capacities. Their logo is h+ — that is, “humanity plus,” for improved humans.

Transhumanists argue that our advancing technologies offer us the opportunity to escape the constraints and cruelties of an amoral evolutionary process, to lift humanity to its next level of personal and social flourishing as genetically enhanced human/machine-hybrid “posthumans.”

On a less dramatic level, many point to the steady increase in medical interventions for purposes “beyond therapy.” The traditional role of medicine has been to cure disease and alleviate suffering; to restore and sustain the patient to a natural level of functioning and well-being. The medical arts were in the service of a wider reverence and respect for the order of the created world. This idea was put succinctly by the Roman physician Galen (in his commentaries on Hippocrates) when he said, “the physician is only nature’s assistant.” But now, with the powers of our advancing biotechnology, there is a new paradigm, one of liberation: technological transformation in the quest for happiness and human perfection.

Grounded in the widespread practice and general acceptance of cosmetic surgery, slowly but steadily the scope and purposes of medicine are being extended along the gradient of our appetites and ambitions to encompass dimensions of life not previously considered matters of health but natural human variation or limitation.

From Rogaine for baldness, growth hormone for shortness, to birth control pills, and Viagra — and more recently Provigil (a drug that allows prolonged periods of wakefulness) and Seasonale (a technological bypass to the monthly periodicity of the natural menstrual cycle) — in all these ways we have altered and revised the given frame of nature. Increasingly, we have come to expect from medicine not just freedom from disease, but freedom from distress, struggle and even the constraints of a natural life process — from all that is unattractive, imperfect or just inconvenient.

As we gain increasing control over the very molecular basis of life, we need to pause to consider carefully how we should proceed. Within both the scientific community and the general public, there is wide recognition that our new gene-editing tools are a “threshold technology,” an opportunity for us to re-envision and re-order our place and purpose within the natural world. The issues involved go beyond biology — our whole sense of personal and social destiny may be hanging in the balance.

The environmental thinker Aldo Leopold offered a maxim that could be useful in this context:

If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.

There is much that we do not yet understand in our biology, including the causes and nature of traits that would seem to impose struggles and constraints on our aspirations. We must not be so foolish or arrogant as to ignore the natural foundations that underlie our human freedom. And just as the human body has been assembled into an organic whole, our civilization is assembled out of cultural, philosophical, and spiritual principles and traditions that should not be casually discarded. The very future of humanity may depend upon this.

Discussion Questions:

1. What difference is there between changes to humanity through natural processes of evolution and directed technological methods like CRISPR/Cas9?

2. What would you want to change in the human genome? What would you want never to be changed?

3. Can we draw reliable distinctions between genetic “therapy” and “enhancement”?

4. Is the essence of humanity contained in the human genome, and would it be changed in the genome were significantly edited? Or is it something that cannot be edited?

Discussion Summary

In our discussion, readers raised a number of interesting new questions and delved deeper into many of those already considered in my essay, especially regarding the feasibility and desirability of gene editing technologies and the underlying implications for human nature and biology. A few key points I noted in my responses:

1. Altering the natural form of a single gene will have many affects, and, apart from genetic diseases, rarely will it have a decisive impact on something of central significance in an individual’s life.

2. The open and indeterminate aspect of human nature is close to the core of what makes us a distinctive species. Yet, this extraordinary capacity for freedom is built on a highly specialized and fragile frame of biological features. In our quest for human perfection, it is this foundation and frame that we must be careful not to destroy.

3. It may be quite disruptive if our discernment and selection begins to delve to the genetic depths of many human characteristics, especially if we turn those discernments into active programs of “improvement” at every level of biology and behavior.