Scientists have discovered that changes in agriculture can cause changes in human DNA. A study published in the journal Nature reveals that various agricultural revolutions over time led to dramatic changes in skin color, height, digestion, and other traits.
Populations grew lighter or darker, shorter or taller, depending on the circumstances of their agriculture.
For example, scientists long believed that people were lighter skinned in northern climates compared to southern climates because lighter skin allowed for greater absorption of vitamin D from the sun. However, Dr. Reich suggests in this study that prior to the agricultural revolution, the inhabitants of these northern climes were dark-skinned, just as people further south.
Dr. Reich claims that the shift to eating grains from crops and away from the meat-based diet they consumed as hunter-gatherers–and the resulting decrease in vitamin D in their diet–caused their skin to lighten over time.
Many of these genetic changes occurred relatively quickly, not slowly over eons as scientists once believed. For example, soon after the first cities formed around milk-producing livestock, the LCT gene evolved to allow people to digest milk without getting sick.
As another example, shortly after the domestication of wheat, the gene SLC224A changed to allow greater absorption of protein from wheat. This gene that allowed humans to digest wheat is also responsible for irritable bowel syndrome. Some genetic changes come with a price.
This research opens a new and unsettling question: How is modern agriculture changing the DNA of mankind? Agricultural practices remained fairly static for thousands of years, from the Roman age until the 1950’s. The modern rise of large-scale chemical agriculture is a new agricultural revolution.
The concurrent rise of obesity is the clearest indicator that changes in agriculture can cause changes in our bodies. Our bodies, our physical selves, are linked to farming practices through the food we eat. But what is not so clear is how these changes will influence our DNA.
We are now consuming a vast array of newly-invented chemicals applied as fertilizers, herbicides, and pesticides to our produce, and as hormones, steroids, and antibiotics to our livestock. On top of that, much of our diet is now GMO, or “genetically modified organisms”.
We know that diet can change our DNA, and now the food itself has been genetically altered.
This massive social experiment we are conducting on ourselves sounds more like science fiction than science. Unfortunately, the unseen costs of our modern diet will remain a mystery until they are revealed decades from now in the genes of our children and grandchildren.