Evolution unmasked

Evolution stems from the inability of any organism to always hand down a perfect copy of its DNA to the next generation. For this we can thank factors such as the fallibility of the machinery in living organisms that copies DNA; and the basic instability of DNA when exposed to certain chemicals or types of radiation that have always existed in our environment. It means that nobody has ever inherited a perfect copy of their parents' DNA. Indeed, one of the reasons we have two parents is to ensure that, if one copy of our genes going wonky, we have a second back-up gene to cover.

When our DNA mutates, natural selection steps in — and this is where things get really ugly. Natural selection is the process through which the mutations in a species which are "best suited" to their environment thrive, while "less suitable" ones die off. It has dictated everything we see around us, from the length of giraffes' necks to the shape of sharks' fins.

In the past, our ancestors were subjected to full-strength, undiluted, CFC-free, pure-organic, additive-free natural selection. The biggest recipients were young children, for which evolution had the greatest appetite of all. Those with the least useful mutations could look forward to a horrific death by starvation, predators, cannibalism, disease, drought, flash floods, drowning and much more besides. During an average 30 to 40 year human life span, mothers would produce eight to 10 children only to see four to five of them die before reaching the age where they might pass their genes to the next generation.

This was evolution writ large: the inexorable cruel erosion of the vast majority of individuals, who had one set of genes, in favor of the tiny lucky minority who had the genetic ability to survive until they could perpetuate this cruel cycle. By running that little bit faster than their brother or sister, the genetic winners avoided getting ripped apart by a pack of hungry wolves. While they clung to life in times of famine or disease, they watched their siblings fade and die. If we believe the human diversity data, we are a species which was reduced to only around 600 individuals over 100,000 years ago. This is the reality of where we came from, of how "Mother Nature" shaped us as individuals.

Unfortunately, of course, humans are still evolving today. People are still dying from disease and starving from deprivations perpetrated by unequal societies and a lack of access to food and medicine. We remain at the mercy of natural selection, the least moral way for a species to develop. And for the majority of us who deplore cruelty and feel compassion for our fellow man, woman and child, I would argue it creates a moral obligation: to aggressively stop evolution of the human species as a matter of urgency.

The only way to do this is to embrace the results of scientific enquiry. Our greatest achievement as a species has been to break free from the sheer naked ferocity of evolution. It means we need GM food to avoid starvation. We need additives to ensure that the food we grow can be safely consumed before it spoils — an important consideration for an increasing population. And most importantly of all, we need vaccines to prevent disease. We must never again expose our children to the wholesome, fully organic, unblemished and obscene fury of Mother Nature unleashed. Love science, hate evolution. Coming to a car bumper sticker near you soon, I hope.

Alasdair Mackenzie, Reader, Molecular Genetics, University of Aberdeen

This article is republished from The Conversation under a Creative Commons license. Read the original article.