You Say Our Genes Don’t Change?

July 4th, 2013 by MorganDowney Leave a reply »

Whenever one raises the genetic aspects of obesity, there is usually a casual dismissal, “Our genes don’t change that fast.” So this  is premised, I believe, on the view that obesity is only a phenomenon arising in the last few decades and our learning somewhere that human genes are relatively immutable. As to the first point, there is ample evidence that obesity existed in ancient times. The environment at that time probably prohibited it becoming as prevalent as it is now. But it was certainly part of the range of human body shapes. More recently, trends of increasing height and weight can be traced back 300 years.

Now comes an interesting report that people living in the Ganges River delta where cholera is endemic have developed genetic variations. Researchers also found changes in genes to protect against arsenic. In both these cases, reports Nicholas Wade in the New York Times, natural selection took place within the last 5,000-30,000 years.