A new Australian study says we are paying the price for cheating natural selection
May 16, 2016 | News | by The Learning Press staff
Modern medicine is cheating natural selection and causing an explosion in the global rate of type 1 diabetes.
New Australian research has found sufferers are now living long enough to pass the disease on to their children, causing a rapid rise in new cases.
The University of Adelaide study into the prevalence of type 1 diabetes in 118 countries and changes in life expectancy from 1950 to 2010 found its rise was directly linked with higher life expectancy in western countries.
"Up to the early 20th century, type 1 diabetes was a horrible and dangerous disease, usually leading to people's death during their teens or early 20s," said lead author Wenpeng You, a PhD student at the university’s School of Medicine.
"This meant there was limited opportunity for people with the disease to have children and to pass their genetic material onto future generations.
“In evolutionary terms, this is what we call natural selection.”
With the widespread introduction of insulin in the 1920s and general improvements in modern medicine, life expectancy for people with type 1 diabetes now stands at 69 years.
"That is a remarkable achievement, but it also means that with reduced natural selection, the genetic material leading to the development of type 1 diabetes may be accumulating at a rapid rate within the world's population," said Mr You.
The researchers decided to investigate the link because, although cases of type 1 diabetes have been increasing globally, its prevalence is uneven in different parts of the world.
"Not every country has access to good health care, or freely available insulin,” said Mr You.
“In a number of poor countries, such as in Africa, the life expectancy for people with type 1 diabetes is much lower than in the western world.
“This means more people are dying prematurely, with less opportunity to produce offspring who will carry those genes from generation to generation."
Co-author Professor Maciej Henneberg said: "Natural selection is one of the major evolutionary forces that inform changes in our genes, across populations and over generations.
"This is the first major disease we have shown that is accumulating due to a relaxation of natural selection over time.
“It's unlikely this situation will ever be reversed, meaning that in order to overcome the problems associated with type 1 diabetes for our population, some form of gene therapy to repair the faulty genes may need to be considered.”
The study, published in BMJ Open Diabetes Research & Care, involves data for type 1 diabetes only and has no relevance for type 2 diabetes.