Scientists might have figured out why some twins are born identical, while also bringing them closer to treatment for congenital disorders.
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As reported first by The Guardian, to the uninitiated, identical twins are formed after a fertilised egg (commonly known as a zygote) splits into two embryos. These embryos contain identical genes as one another. And the reason for this is unknown.
Some believe that the biological process resulting in monozygotic twinning is random in nature. However, now researchers from the Vrije Universiteit Amsterdam are of the belief that they¡¯ve found a common signature on the DNA of the identical twins dubbed epigenome.
The study looked at the epigenetic modifications in twin¡¯s DNA, factors that they can turn the genes on or off without changing their underlying sequence. Researchers discovered that identical twins across the world had similar marks at 834 points across their genome.
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According to the scientists, these marks allow researchers to determine whether an individual is an identical twin, including those who don¡¯t know if they lost their twin in the womb, also commonly known as the vanishing twin syndrome with 80 percent accuracy.?
Around 12 percent of human pregnancies could start as multiple embryos (twins) but just 2 percent carry to term with many even unaware of the fact that they had a twin.?
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Professor Dorret Boomsma of the Netherlands Twin Register (VU), who specialises in genetics and twin studies said, "This is a very big discovery. The origin and birth of identical twins have always been a complete mystery. It is one of the few traits in which genetics plays no or very modest role. This is the first time that we have found a biological marker of this phenomenon in humans. The explanation appears not to lie in the genome, but in its epigenome.¡±
This theory is yet to be proved as there is a possibility that this could be a consequence of the twinning process, however, it is said to be a plausible working theory where the discovery of the common marks could prove helpful in a wide variety of people.