genetics

 

The discovery of Epigenetics – hidden influences upon our genes – will affect every aspect of our lives. Biology stands on the brink of a shift in the understanding of inheritance.

At the heart of this new field is a simple but contentious idea – that genes have a ‘memory’. That the lives of your grandparents – the air they breathed, the food they ate, even the things they saw – can directly affect you, decades later, despite your never experiencing these things yourself. And that what you do in your lifetime could in turn affect your grandchildren.

The conventional view is that DNA carries all our heritable information and that nothing an individual does in their lifetime will be biologically passed to their children. To many scientists, epigenetics amounts to a heresy, calling into question the accepted view of the DNA sequence – a cornerstone on which modern biology sits.

Epigenetics adds a whole new layer to genes beyond the DNA. It proposes a control system of ‘switches’ that turn genes on or off – and suggests that things people experience, like nutrition and stress, can control these switches and cause heritable effects in humans.

In a remote town in northern Sweden there is evidence for this radical idea. Lying in Överkalix’s parish registries of births and deaths and its detailed harvest records is a secret that confounds traditional scientific thinking. Marcus Pembrey, a Professor of Clinical Genetics at the Institute of Child Health in London, in collaboration with Swedish researcher Lars Olov Bygren, has found evidence in these records of an environmental effect being passed down the generations. They have shown that a famine at critical times in the lives of the grandparents can affect the life expectancy of the grandchildren. This is the first evidence that an environmental effect can be inherited in humans.

In other independent groups around the world, the first hints that there is more to inheritance than just the genes are coming to light. The mechanism by which this extraordinary discovery can be explained is starting to be revealed.

For any mother who had her first child by in vitro fertilization, this has profound implications, because the switches in question could be inherited and a memory of an event could be passed through generations. Meaning a simple environmental effect could switch genes on or off – and this change could be inherited.

New research has demonstrated that genes and the environment are not mutually exclusive but are inextricably intertwined, one affecting the other. This raises questions with huge implications, and means the search will be on to find what sort of environmental effects can affect these switches.

This work is at the forefront of a paradigm shift in scientific thinking. It will change the way the causes of disease are viewed, as well as the importance of lifestyles and family relationships.

What people do no longer just affects themselves, but can determine the health of their children and grandchildren in decades to come. "We are," as Marcus Pembrey says, "all guardians of our genome."

     

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