Studies on twins have revealed the genetic nature of many medical conditions, including autism and ADHD. Now they're giving us unnerving insights into many behavioural traits too.
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IMAGINE RECEIVING A PHONE CALL out of the blue. You find the voice on the other end eerily familiar as it tells you some life-changing news: you are, in fact, a twin. And when it comes time to meet face-to-face, you find it’s like gazing into a mirror. You share a similar dress sense, hairstyle and even idiosyncratic gestures and expressions you thought were uniquely yours.
In 2004, Paula Bernstein found herself in exactly this situation when she was contacted by Elyse Schein, who broke the monumental news that they were twins, separated at birth and raised apart.
They met for the first time at a New York café, where nerves and trepidation soon gave way to warm conversation. “We had 35 years to catch up on,” says Bernstein. “How do you start asking somebody, ‘What have you been up to since we shared a womb together?’ Where do you start?”
“It was really surreal,” agrees Schein. “It was like meeting an alternate version of myself.” She found the similarity in mannerisms particularly spooky. “I always had the idea that [the way] I gesticulated – raised my eyebrows and so on … was due to my environment, but now I know it’s inherited.
We joke sometimes that we want to turn off each other’s mannerisms, because it’s unnerving to see them echoed back.”
AND IT WASN’T ONLY idiosyncratic gestures that the two had in common. Despite being raised by different families in disparate parts of New York City, they both followed an uncannily similar path in life.
“We were each editor-in-chief of our respective high school newspapers and then went on to study film theory,” says Bernstein, who is now a journalist, while Schein went on to become a writer and film-maker.
Cases like that of Bernstein and Schein are rare these days, but they give a compelling insight into the role that genes play in shaping the fundamentals of who we are. “Twins really do force us to question what is it that makes each of us who we are,” says Bernstein. “Since meeting Elyse, it is undeniable that genetics play a huge role, probably more than 50%.”
In fact, Bernstien and Schein, who documented their experience in their book Identical Strangers, were separated as a part of a secretive scientific study of nature versus nurture conducted by child psychiatrist Peter Neubauer in the late 1960s. Such experiments wouldn’t be possible today for ethical reasons, but identical, or monozygotic twins still represent an incredibly valuable resource to science.
“They are a beautiful natural experiment,” says Nicholas Martin, geneticist at the Queensland Institute of Medical Research and editor of the scientific journal, Twin Research and Human Genetics. According to Martin, identical twins give scientists the perfect opportunity to tease out genetic and environmental variables from factors such as personality or susceptibility to diseases including asthma, depression, alcoholism and attention-deficit hyperactivity disorder (ADHD). And it’s all because identical twins are effectively natural clones.
Non identical clones and free will!
Although it's based on a single observation, the example of genetically identical 68 year old brothers who are very different might illustrate the power of epigenetics translating choices into corporeal expression.
My friends are so different that I would not have expected them to be brothers let alone identical twins.
The key difference is in temperement, and this then seems to have resulted in choices that have driven their development apart.
One brother A is friendly and sociable, the other B sullen and greedy.Their faces and body language reflect this difference.
A is healthy, muscular 180 cm.
B is unhealthy obese 185 cm.
I expect that A will live several years longer and enjoy life much more than will B.
While the above article has pointed out the power of our genes, as individuals we have the ultimate control over our fate by the choices that we make be they conscious or instinctive.
By deliberate intelligent choices to adopt good habits, we can all do the best we can with what we have.
Best wishes Ron Horgan