What does it mean to be unique? Twins and epigenetics
Everyone is unique. Or at least that is what we are told, but how true is it? When scientists identify each of us as unique they are commonly referring to our genetic make-up, our DNA; the stuff that will define whether our hair is curly, or our eyes are blue. But are we all unique? Many of us will either know first-hand, or be aware of the fact that there are people in the world that look incredibly similar. These people are commonly referred to as identical twins, or in the scientific world monozygotic twins.
Identical twins: Rolling the dice
Fertilisation occurs when a single egg becomes fertilised by a single sperm forming a fertilised egg, or in scientific speak a zygote. This zygote, in the vast majority of instances will develop into a single embryo (estimated to occur in 997 of 1000 births). However, occasionally it will split and develop into two embryos (estimated to occur in 3 of 1000 births) resulting in monozygotic (one-egg) twins. These individuals share the exact same genetic material other than small mutational differences that may be introduced during development. So… does that mean that not everyone on the planet is unique? Well… No, not exactly!
Fingerprints are unique
Genetics provides a blueprint, the instruction manual for building you. However, unlike most blueprints that humans use to construct houses or design cars, our genetic blueprints are dynamic. They are affected by the environment. The world in which we develop impacts how we develop. For instance, even though identical twin's DNA is exactly the same, they don’t have the same fingerprints. Why? Because minute differences in their environment whilst still in the womb affects how their fingerprint ridges develop.
From fingerprints, to physique and behaviour
The differences between identical twins, doesn’t end at the tips of their fingers. How we end up, although controlled to an extent by each of our genetic blueprints, is in large part dependent upon our environment. For instance, identical twins can differ in their height and weight because of dietary differences, serious illnesses or even differing placental connections whilst still in the womb. And it’s not just physical attributes that are affected by our environment. Scientists are now starting to understand that our behaviour and the continuing development of our brains is in large part a result of our environment too.
A mother knows
“In twin studies it had been clear that even though the twins are identical (monozygotic), there are still some differences between them that emerges over time,” says Gerd Kempermann, a behavioral geneticist at the Dresden University of Technology and the German Center for Neurodegenerative Disease in Germany. “Identical twins are often amazingly similar, but mothers and close relatives can still tell them apart easily.”
Our path through life is what makes us unique
Although some among us start life identical; even before we leave the womb our environment has ensured that each and every single one of us is unique. As we move through life these environmental differences become increasingly important for our health and wellbeing. With small environmental differences resulting in large health and lifespan differences.
Measuring your environment, one epigenetic mark at a time
Our environment affects us by altering expression of our genes. These expression alterations are stabilised and maintained by a layer of information called epigenetics. As we grow older and experience ever diverging environments this epigenetic information comes to represent a history of how our environment is imprinted on our DNA and what we can do to reverse aspects of it.
But how to measure these epigenetic changes?
Enter Chronomics, a revolutionary healthtech company with a mission to help each of us stay youthful and healthy for longer.
Tom Stubbs is CEO and founder of Chronomics