Germline Engineering: the Next Stage in Human Evolution?

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Humans traditionally evolved through survival of the fittest (natural selection). This is no longer the case. We have reached a stage of medical advancement where almost everyone has the opportunity to survive and reproduce, regardless of how fit they are. This results in an accumulation of harmful alleles in our gene pool, and will eventually result in ‘negative evolution’. Fortunately, there is a way to combat this negative evolution: germline engineering. 

Germline engineering is a special case of genetic engineering, where the genetic changes made to an individual are heritable, so they will be passed on to the next generation. This is achieved by making genetic changes to reproductive cells, such as the precursors to sperm and egg cells. This process can be used to eradicate genetic conditions, but also to enhance existing genes and even introduce new genes, paving the way for controversial concepts such as designer babies and eugenics.

Conventional gene therapy can be used to treat conditions ranging from diabetes to some cancers, but the therapy only affects the individual who is being treated. If the condition is heritable, the individual’s offspring would still be at risk of inheriting it. With germline engineering, reproductive cells can be targeted to ensure that all future progeny of the individual are devoid of the condition, and it is eventually eradicated. There are other conceivable ways to eradicate genetic conditions, but germline engineering would be the most effective.

Many scientists argue that germline engineering should be limited to medical applications. This was the view of a global panel of genetics experts in March 2017:

At this time, given the nature and number of unanswered scientific, ethical, and policy questions, it is inappropriate to perform germline gene editing that culminates in human pregnancy.

Future clinical application of human germline genome editing should not proceed unless, at a minimum, there is (a) a compelling medical rationale, (b) an evidence base that supports its clinical use, (c) an ethical justification, and (d) a transparent public process to solicit and incorporate stakeholder input.

The group provides a long list of ethical justifications to back up their stance, but they do not delve into the potential benefits of using germline engineering to make non-medical improvements to our population.

If germline engineering were to be rolled out across the whole population, we could avoid the creation of a designer baby movement. Instead of parents choosing enhancements for their children, government and society could decide on specific enhancements that would be implemented across the entire population.

There is a gene mutation that allows a few lucky people to function normally on 4-6 hours of sleep. With germline engineering, we could make this gene mutation ubiquitous in the human population. Maybe with a few more leaps we could engineer ourselves to a point where we can function with no sleep at all. Another interesting option would be to incorporate fish antifreeze proteins into our genome, as has already been done with tomatoes.

These changes would be awesome, but progress in the field is slow: it’s difficult to obtain funding for research because of legal and ethical issues. Despite this, a Chinese team has successfully modified non-viable human embryos, but they advise that much more work is needed before we are able to safely modify embryos that are intended to be implanted.

In the near future we may gain significant control over the evolution of our own species. This would mark a significant milestone for humanity: we would essentially have god-like powers, which is scary, but exciting.


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