Grits and Purls

Spinning yarns about the grit of life


For quite some time biologists have debated whether or not any natural selective forces could act on modern humans to influence the makeup of the human genome. The argument against modern humans, at least those in developed countries, being subject to natural selection says that because of the technologies and medicines that we have developed to keep us alive, there is no room for natural selection, and even if natural selection is acting on modern humans, seeing that activity above the “noise” of technological, scientific and medical advances would be virtually impossible.

Because of advances in technology, science and medicine, people who previously would not have produced children, now do with the help of assisted reproduction. Babies who would not have survived to adulthood now do because of modern medical intervention at the earliest point in their lives. Medical technology now allows people who would have died from genetic diseases early in life to live long, full lives that include producing offspring. In a sense these advances in medicine and technology have “leveled” the genetic playing field, and allowed society to benefit from the hearts and minds of individuals, who in an earlier era might not have survived.

Therefore many biologists argue that these same advances of humanity have rendered natural selective forces ineffectual for modern humans.

But of course, Nature always has the final word.

Recently a group of scientists has reported evidence that there are natural selective forces shaping the human heart through selective pressures on the genome. The current finding is based on the massive amount of data generated by the Framingham Heart Study begun in 1948. This study was the first to show that smoking, high cholesterol and obesity increase a person’s chances for developing heart disease.

Researchers at Boston University took a second look at the data from this study, which followed families for multiple generations. What the early results show is that women with lower cholesterol, blood sugar, and blood pressure, all had more offspring than other women (controlling for factors like economics and education). This means that the genetic makeup that contributes to lower cholesterol, blood sugar, and blood pressure will be slightly more prevalent in the resulting generation, and that the next generation will also pass these “good heart” traits on at a higher frequency.

This is interesting biology, and fascinating to population geneticists. However, I must confess that when I first read the title of an article summarizing this research, I had hoped that I would read about research that showed a trend toward altruistic behavior and kindness in the modern human population. That people were more likely to engage in charitable acts that help the other members of society have better lives, and that this kindness and compassion could become hard-coded in our genome.
But, it may be that natural selection is not what we should be relying on to help us develop into a kinder, more compassionate species. It may be that we should be using our brains to develop compassion, just like we use our brains to develop new technologies to save or extend lives.

Every day we read about anger and depression, and desperate and desperately lonely or angry people doing desperate things that irrevocably hurt those around them. We live in a world that cries for compassion. We need to start walking the mile in the other person’s moccasins before judging her. We need to stop and do the simple little thing that might help someone out—the coin in the Salvation Army bucket, the school supply donations, the food pantry gifts.

We need to model kindness and compassion to the future generations who will inherit the strong heart genetics so that those future generations not only have strong hearts, but will also have kind hearts.

© 2009 Michele Arduengo. All rights reserved.

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