Twins have the same DNA but they do not always look identical. What makes them look and act differently are the differences to their epigenetic profile. Australian researchers have followed more than 200 sets of twins to learn more about this area of science.
While genetics is the study of inherited genes, epigenetics looks at changes in the activity of genes that do not involve alterations in the genetic code but still get passed down to at least one successive generation.
Richard Saffery a researcher at Murdoch Children’s Research Institute in Australia explains: “Epigenetics basically refers to a series of chemical and other modifications that regulate how our genes behave, it tells a gene whether to be on or off, turns it up or turns it down. It controls basically all gene activity.”
Epigenetics can help explain why one of a pair of twins – with the same genetic code – can develop a condition like asthma even though the other doesn’t.
Jeff Craig who is also a researcher at the Murdoch Children’s Research Institute said: “We’ve measured epigenetic marks of the twins within the identical twins at birth and we’ve measured the levels of gene activity that these epigenetic markers govern and we found that they can be quite different at birth. So, most of those differences must have accumulated while these twins were in the womb. Some of our so-called identical twins with the same DNA, their mothers don’t believe their identical because they can look so different.”
Changes in genes are important. They can influence a person’s health and even lead to complications in later life.
Richard Saffery added: “We’ve just recently shown for the first time that a change in epigenetic profile translates to a change in gene expression and we all know that changes in gene expression underpins all human disease, so it’s potentially quite profound.”
It is through epigenetic marks that environmental factors like diet, stress and pre-natal nutrition can make an impression on genes. This can be passed from one generation to the next.
There is evidence that lifestyle choices can change the epigenetic marks in your DNA. For example, if you eat too much the genes for obesity can express themselves strongly.
Some have recommended an ‘epigenetics diet’ which includes broccoli and tofu – foods that can help reverse negative changes to gene expression.
Epigenetics seems to confirm the saying “You are what you eat”.