Scientists in Sydney, Australia, have turned the widely accepted understanding of ‘natural selection’ on its head, showing that desirable traits and characteristics, such as being lean and healthy, can become more common in a population over generations, without the need for a change to our genetic code.
Gene tweaking: could we turn our biological destiny around?
The team at Sydney’s Victor Chang Cardiac Research Institute (VCCRI), show that traits can become steadily more prevalent in a population via ‘epigenetic changes’, but that these changes can also be reversed. Epigenetics is an emerging area of research that looks at how genes are switched ‘on’ or ‘off’, often through an environmental change.
Using a mouse model, the team of researchers fed their subjects a diet rich in supplements such as folate, zinc and vitamin B12. The diet suppresses obesity in mice by turning a particular gene ‘off’.
They found that when the diet was continued in the lean mice over five generations, these ‘epigenetic’ effects were inherited, and the proportion of lean and healthy mice in each subsequent generation increased, without any change to the genetic code of the mice.
Dr Cath Suter, Head of the Epigenetics Laboratory at the Victor Chang Institute and the study leader, says the most compelling aspect of the findings is the reversible nature of the diet-induced epigenetic changes, unlike genetic changes which cannot be reversed.
“When we took the diet away from the mice, we found that the proportion of healthy and lean mice stayed the same for a generation or two, but then dropped off again,” she says. “This kind of reversibility could be very advantageous if a change in environment was only temporary, say, a change in climate. Populations could adapt quickly but retain the ability to revert back if necessary.
“These findings could have implications for a number of other trends and changes in our population, such as the obesity epidemic that we’re seeing all over the western world right now,” added Dr Suter.
Victor Chang researcher and co-author on the study, Dr Jennifer Cropley says that we can no longer accept the idea that evolutionary changes only occur through genetics.
“Over the years we’ve come to accept that genetic changes underlie Darwin’s theory of evolution and natural selection – that a chance genetic mutation occurs in a person, and if it’s desirable or advantageous, it will be passed on through generations and eventually populations.
“What this study gives us is a new way of understanding how we might have evolved and how populations can rapidly adapt to new environments,” said Dr Cropley. “Genetic changes take many thousands of years to spread through a population – but with epigenetic changes, a whole population could change much more rapidly, because epigenetic changes can occur in multiple individuals simultaneously and potentially be passed on by all of them.”
The research, published today in the journal Proceedings of the Royal Society B, follows another recently published study by the same researchers that showed that epigenetic marks can be followed over evolutionary time scales. Suter, Cropley and colleagues from the University of Adelaide found epigenetic signatures in DNA from 25,000 year old extinct bison.
“This is an exciting first step towards testing the idea that epigenetics can drive evolution, not just in the laboratory, but in natural populations as well,” added Dr Suter.
The research is part of a larger study into what the epigenetic effects of diet are and how it affects the future disease risk of offspring.
About the Victor Chang Cardiac Research Institute
Established in 1994, the Victor Chang Cardiac Research Institute (VCCRI) is committed to excellence into heart disease and cardiovascular biology research, cardiovascular research training and facilitating the rapid application of research discoveries to patient care. In Australia alone, heart muscle diseases – the cause of heart failure – are responsible for the death of over 130,000 people annually with 400 new cases being added each week. For more information visit www.victorchang.edu.au
For further information and interview requests, please contact: Anna Dear, Victor Chang Cardiac Research Institute P: +61 (2) 9295 8715 M: +61 404 637 607 E: firstname.lastname@example.org