Good evening all,
As I indicated during class on Wednesday, we will not meet for lecture tomorrow (Friday 22 Nov), but instead will consider some topical science news:
We finished one of our recent lectures by introducing the concepts of gene therapy and cloning. Both of these stem from the application of modern genetic methods, and both exist already - but not without controversy.
As described in your text, gene therapy is an attempt to correct defective or missing genes, by using viruses to insert them into a person's cells. It remains very controversial and of relatively limited use, because many of the risks and complications of the technique have yet to be overcome. Indeed, some human gene therapy trials have resulted in patient deaths, and few would say that the technique has been proven to the point at which broad use is possible. Still, for some people with very specific types of genetic defects, gene therapy has proven to be a lifesaver (literally). We can expect to continue to hear much about gene therapy in the years to come.
Related to gene therapy is the concept of gene editing. The goal of this technique is not to replace defective genes with normal copies, but rather to use enzymes to edit (correct) the defective genes in place (e.g., within the cells of the organism). Gene editing utilizes techniques more recent than those employed in gene therapy, so it has been tested, and used, relatively less. Thus, it was of great surprise to the scientific community last Fall when a Chinese scientist (He Jiankui) claimed to have performed gene editing on several artificially (in lab) created human embryos, and then to have implanted those embryos into female surrogates to carry the developing embryos until birth.
The technique of gene editing is new enough that, one year ago, the ethical guidelines governing its use had not been fully developed. Nonetheless, there was a general understanding that the technique was not to be used in human embryonic tissue, that would result in *all* cells in the body inheriting the edited gene. This understanding was very broad, but was not universal, and scientists in several countries did use (or attempt to use) the technique on human embryos, in the hopes of creating a gene-edited person - a "designer baby".
The scientific backlash against this first report of human embryonic (germline) gene editing was relatively swift, and relatively severe. The scientist who conducted these first trials has been stripped of his research position, and charged with violating his country's biomedical research laws. The infants (twin girls) were reported to have been born, but little is known about their condition. Some researchers have suggested that they are at risk of a shortened life expectancy because of the gene editing. The gene that was edited in these now-children is thought to promote resistance to HIV infection, but also seems to play other roles in cells.
The article I am forwarding here comes from a few months ago, when the investigations into this researcher and his colleagues was still in process. In particular, there were a number of scientists here in the U.S. who were implicated as having supported this work. The researchers here have generally been cleared of any wrongdoing, but significant questions remain about who knew what, and the motivations (money? fame? patent-able technology?) for their involvement. This article also includes links to a number of related stories, of which there are many.
It is worth noting that somatic (non-germline gene editing) is gaining ground as a very powerful and promising technique. This variant of gene editing does not change the DNA in every cell in one's body, but only in focal tissues (such as a single organ) that may be malfunctioning due to a defective gene. Indeed, news reports of the promise of this (more-limited) application of gene editing are also prominent in the recent news, including:
I suspect that your generation will be forced to come to terms with the promises and perils of gene editing - it seems both incredibly promising, and incredibly dangerous at the same time. Having a robust set of regulations and ethical guidelines will be very important. If you were faced with the opportunity to correct a gene in yourself, in a loved one, would you? That's a very difficult question to answer a the moment, as we do not yet have enough experience with the pros and cons of these techniques. But, the evidence is beginning to accumulate...
Here's wishing you all the very best Thanksgiving break - please be safe, rest, relax, eat, and enjoy.
Leave a Reply.