“The Secret Life of Twins”
September 29th, 2009
Two middle-age women, Sue and Sheila, are born as identical twins, but one of them is aging faster by 10 years. Two identical twin brothers are so alike their hair went grey at the same time, but one of them cannot tolerate pain as much as the other. And there is a six-year old girl who was diagnosed with leukemia but her sister is completely healthy.
Identical twins are monozygotic – they come from the same single egg that split early in development, and therefore share the same exact DNA, so we expect them to look alike, have the same personality and experience life the same way. But scientists say that each individual is still very much unique from the other. Why?
It’s a process called epigenetic – when non-genetic factors cause the gene to behave or be expressed differently.
Like the two women above. Daily Mail UK relates that Sue had a much more traumatic life as a married adult. She smokes, does not eat healthy and put on weight, whereas Sheila has an easier and healthier life. When scientists looked at the women’s chromosomes, they found that the telomere on Sue’s chromosomes were shorter than Sheila’s. Research shows that shorter telomeres are associated with the aging process. Because of Sue’s life was more harsh, her telomeres had grown shorter and she has aged 10 years faster then her twin Sheila.
And then there are identical twins who have been raised apart their whole lives – from the US and Norway, and yet the twins are still so alike that one questions how much influence parental upbringing actually has.
BBC ONE has a documentary titled “The Secret Life of Twins” that attempt to understand the age-old debate of “nurture versus nature”. It will be shown on 30 September and 01 October 2009 at 9.00pm. I think this will be an interesting look at how complex the human being really is.
Image: sxc.hu/greyman
Post from: Genetics & Health
Entry Filed under: genes