Could our own evolution provide clues for new medical treatments?
Any of you who indulge in reading a good science journal from time to time, be it Scientific American, Nature or New Scientist, will probably have noticed the increased appearances of certain areas of research. In fact, the biologists, medics and anthropologists of you will probably be very taken with the way the Vogues of the science world are publishing your areas of study like they are the haute couture of revolutionary research. Medicine, genetics and biological anthropology are some of the hottest topics on the scene today. What I’d like to ask you is this; why shouldn’t they be? With the repeated scares of new strains of the influenza virus, increasing reports of antibiotic resistance in human pathogens and an ever expanding population of us great, walking, microbial hosts, these subject areas are becoming ever more relevant to the public.
As a biomedical student who also studies human evolution, not only do I find combining my knowledge from both areas rather interesting, but it has also occurred to me that, rather than always being one step behind the virus, scrabbling to keep up with each medical corner turned, consistently finding ourselves bested by the likes of antibiotic resistant E.coli or Streptococcus, it might make far more sense to think in terms of war tactics, and to find some way of gaining predictive knowledge so that we can be one step ahead of the diseases we are battling to eradicate. With foresight into the future of our physiology we could predict the changes in our adaptive immunity and survival when faced with these stubborn pathogens.
It is important to recognise, however, that viral and bacterial evolution isn’t a new thing, or an absolute disaster. Just as all living organisms on this planet, they have been, and always are evolving. The reason humans haven’t died out long ago is the phenomenon that is our immune system. Our immune system not only contains innate immunity; the immunity we’ve inherited over generations and generations, but also adaptive immunity, which occurs as a response to our own, individual experiences of pathogens. From this we form immunological memories so that if we are faced with the same nasty bug again, we’re able to kill it off without much trouble at all. It is important to consider that, as discussed in Frank Ryan’s book, ‘Virolution’, viruses are part of the same ecosystem that we are. In some way, they contribute to the necessary order of things just as we do, if not more so. There have been a multitude of discoveries about our very own genome which is shown to contain viral genetic material. Research at the University of Texas has estimated that the DNA of humans and other mammals contains up to 8% viral RNA. Viruses that integrate their own genetic material into the chromosomes of cells involved in reproduction are said to undergo endogenisation. Some of these viruses are thought to be responsible for disorders such as schizophrenia, which may provide us with an answer to the treatment for psychiatric disorders in the future. So if a virus can have such a considerable negative influence on human evolution, it isn’t unlikely that some beneficial physiological traits we have today are a result of viral endogenisation. The bottom line is this: viruses aren’t all bad.
However, with selective pressures such as the use of antibiotics and medication, pathogens are being forced to adapt and so are growing resistant. Equally, by mollycoddling our immune systems it may mean that evolution of our immune systems is slowing as the pressures that would have been presented by new pathogens and exposure to infections are no longer given a chance to act. As a result, the following generation will be no different in their ability to fight disease, but the pathogen may have evolved to become resistant to medication. This means that, with the sociological pressure to treat every cold and cough, we are looking for more and more ways to keep ahead in the evolutionary race against our biggest (and smallest) predators through the use of medication.
For millions of years we’ve survived through climatic change and bouts of terrible disease. Something in our genome, in our bodies, has allowed us to prevail despite all of these challenges. It is more than probable that this is our adaptability, our flexibility as a species. Could it be possible, by looking at the physiological changes that have occurred over millions of years that we could predict future changes and tailor our medicinal treatments to them?
This kind of knowledge could be useful on two levels; in anthropological studies of population genetics, and a more natural approach to gene therapy, or the use of germ line therapy for direct and rapid change. For example, we could take into consideration the plethora of selective pressures that are acting upon us at any one time, and we could consider recent changes in our genome and the implications they have had on us as a species. We could, by looking at our biological history, identify a trend and the future path we will take through evolution. If we did this, as well as applying the same principles to life threatening pathogens, we could attempt to anticipate which changes will help us in the war against disease. This knowledge could even allow us to gain insight into how we are evolving this very minute, and perhaps simulate selective pressures within the population which would allow us to evolve in such a way that would mean we are more resistant to deadly pathogens. Alternatively, with the advancements of gene therapy, if we were to discover the genetic mechanisms which preceded these immunity phenomena, it would be possible to anticipate evolving traits in pathogens, and adjust the genetic make-up of our own immune system over time, allowing us to evolve in such a way as to prevent epidemics.
This synthetic form of natural selection would undoubtedly become a hotspot for scientific ethical debates, just as gene therapy for treatment on an individual basis is now. It would leave windows open for biological elitism, for unnecessary and immoral experimentation, for capital to be gained when people decided to abuse such knowledge for the sake of beauty and aesthetics. However, as with any new medical treatment, if the use of germ line therapy, or more natural allele manipulation was carefully monitored and used sparingly, simply altering the allele frequency in the population, particularly in those who are more prone to producing offspring with a weakness for a disease, the human race would continue to prevail without any ethical hiccups. There will be people out there who speculate whether it would be better to simply let nature take its course, that medicine and science cannot ‘override’ nature – they may well be right. However, if, as a society, we continue in the manner that we do; fighting an uphill battle with treatments and drugs, the struggle will just become greater as we find ourselves in the shadow of viral evolution, threatened by even newer, more foreign strains. If we’re going to do what our human nature tells us to do, and survive, then understanding why we’ve managed it for so long might be just the way to do that. The only way we can truly take one step forward, might be to take two steps back.