Altered expression: Epigenetics and its influence on human development

Tortoiseshell cats get their dappled colouration from X inactivation (photo credit: Tony Hammond via Flickr)
Tortoiseshell cats get their dappled colouration from X inactivation (photo credit: Tony Hammond via Flickr)

Our genetic make-up determines a lot about who we are – it determines whether we have blue eyes or brown, what blood group we have, or whether we’re predisposed to cystic fibrosis or sickle cell anaemia. But we’re beginning to learn that we’re far more than the sum of our genetic parts. Our genes only tell part of the story of who we are.

Just as important as what genes we’ve inherited from our parents, is how those genes are switched on and off throughout our lifetime. This complex system of genetic regulation has been the focus of the burgeoning field of epigenetics.

I was joined on Up Close recently by geneticist Marnie Blewitt. We chatted about epigenetics and her work on one of the coolest areas of epigenetics – X inactivation. Marnie heads a lab that studies epigenetics at the Walter and Eliza Hall Institute of Medical Research.

 

Epigenetics: the ever-changing genetic landscape within us

Even identical twins aren't identical, thanks to epigenetics (Photo: Johannes Lundberg via Flickr)
Even identical twins aren’t identical, thanks to epigenetics (Photo: Johannes Lundberg via Flickr)

Can you change your genes? Until a decade or so ago, the popular understanding of genetics was that you inherited your genetic instruction manual from your parents, and barring potential mutations that you might gain throughout your life, your genes are fixed. Environment does, of course, play a role – there’s no denying that choices such as what you eat and how much you time you spend exercising can impact your health.

But epigenetic markers — chemical changes to DNA that don’t alter gene sequences, but none-the-less modify how our genes are activated or silenced — are emerging as a powerful force in human health and disease. What your mother or father ate before conceiving you, where you, as a tiny embryo, decided to implant in your mother’s uterus, and how affectionately you were cared for as an infant can have long-lasting effects on epigenetic markers, and as a consequence, on your health. Head over to ABC Health & Wellbeing to check out a piece I wrote about epigenetics last week.