Lifeboat Foundation

When was the last time you went through the old family photographs? Imagine doing it now, but in a very different way. This photo collection is titled “Time Machine.” Everyone appears at your present age, and the first picture is of yourself. But next to yours is a picture of one of your parents, whose picture is in turn next to that parent’s parent (your grandparent), then your great grandparent, and so on —
back through time.

Four generations would take you back roughly 100 years. Forty — just a few pages of an old-fashioned photo album or a couple screens of thumbnails — would go back a thousand years. That’s a ways back, but we’re not finished. Four hundred generations would be about 10,000 years. That is a long time, yet the photos would still fit in an old-fashioned photo album, or alternatively perhaps 20 screens of thumbnails. However ten thousand years ago things were very different: no reading or writing (or school), no religion we would recognize today, and many other differences. The neolithic (agricultural) revolution was beginning, and no doubt you can fill in some of the other blanks. Yet, the most distant ancestor pictured, from some 10 thousand years ago, would look much the same as the most recent one — you (except of course for the clothes).

A few significant differences might be invisible, but present nonetheless. If you happen to have Tibetan background, you probably have a gene for high altitude-adapted blood that this ancestor did not have, and similarly if your background is Andean, because those genes spread more recently. Similarly if you have a Scandinavian or East African dairy farming background, you probably have a dairy digestion-adapted gene that this ancestor did not. Has your background has not yet been mentioned but you were still hoping for some evolutionary enhancement to distinguish you from your ancestors of 10,000 years ago? Not to worry much — there may be some and they probably will be discovered soon enough. But when all is said and done, the human of today is mostly indistinguishable from the human of 10 millenia ago.

Similarly humans 10,000 years from now will likely be mostly indistinguishable, physically, from those of today. Some interesting differences may occur, however. The most obvious differences will be cultural, with present-day nations, nationalities and ethnic distinctions, and even religions changed greatly, perhaps nearly beyond recognition. From a genetic standpoint, the most dramatic possibity is that organized selective breeding will occur. Dogs have been bred for about 15,000 years, and it is amazing how much they can differ from each other as well as from their wolf forebears after such a short time. In humans there is little precedent for this process. But there is also little doubt that deliberate selective breeding could potentially produce, in just few generations, super-athletes, super-geniuses, super-wine tasters and so on.

Perhaps slightly less dramatically, a selective sweep could modify the human genome in short order. Consider long-term nonprogressors, the tiny percentage of people who have the HIV virus but do not become ill from it and thus do not need medicine. They do not “progress” to obvious illness. Unless a very cheap and effective cure for HIV is found, over the next 10,000 years the genes that protect these long-term nonprogressors are likely to become the rule instead of the exception.

Another apparently on-going selective sweep relates to alcohol. I recently witnessed a tall man exiting a liquor store on a Friday afternoon with a hefty payload — and the expression and demeanor of naked intent to get home fast and begin another weekend to remember (or forget). The past 10,000 years appear to have witnessed an ongoing selective sweep of the genetic ability to comparatively rapidly metabolize alcohol, clearing it from the body with the enzyme alcohol dehydrogenase. Populations not exposed to much alcohol until more modern times, like native Americans, tend to have higher rates of alcohol abuse. The havoc that alcohol causes abusers and their families is so great that it is nearly inconceivable that licensed sellers can sell it to abusers. Licenses should be required of purchasers. Each license could be a plastic card with an embedded chip that records purchases and permits them only at non-abuse rates.

Currently, the world is so awash in substance abuse that there may be significant genetic selection for resistance to addictive substances. Intriguingly, while some genes apply only to specific intoxicants, like the alcohol dehydrogenase gene, others may affect susceptibility to addiction in general. Why is this intriguing? Because potential for addiction is built into the brain, more in some people than in others. Likely that potential is there for a reason, with the addiction issue present only as an accidental side effect. It might be a good reason; we just don’t know. As addiction is bred out of the human genome, brains, thus minds, thus society will change. But in what ways? The reader might enjoy speculating, because that is about all one can do as the facts are not yet known.

References

“If you happen to have Tibetan background…”: J. K. Pritchard, How we are evolving, Scientific American, Oct. 2010.

“On the other hand if you have a Scandinavian or East African dairy farming background…”: Pritchard, How we are evolving.

“But there is also little doubt that deliberate selective breeding could potentially produce, in just few generations, super-athletes, super-geniuses, super-wine tasters and so on.” R. Dawkins, The Greatest Show on Earth: the Evidence for Evolution, Free Press, 2009.