Study says identical twins may not be so identical after all

If you’re a father of twins, you probably started doing some pretty intense research as soon as you found out you were expecting multiples. Well, it’s time to put everything you’ve learned aside as new research shows that identical twins may not be as identical as people originally thought. Yes, it’s time to relearn everything you thought you knew about your twins.

Although we know that the genetic differences between identical twins start very early in their embryonic development, it has been reported that by looking at the differences between nature and creation, they have more genetic differences than previously thought. the origin.

Study says identical twins may not be so identical after all

Identical twins (more officially known as monozygotic twins) come from a single fertilized egg that then divides into two. Until now, identical twins have always been considered important research subjects due to their minimal genetic differences. Prior to the most recent study, it was believed that any time any behavioral or physical differences arose, they were due to environmental factors or reproduction.

However, according to the new research, published Thursday in the journal Nature Genetics, the co-author of the article, Kari Stefansson, believes these differences have been underestimated.

“So if you take identical twins raised separately and one of them develops autism, the classic interpretation is that it is caused by the environment. But this is an extremely dangerous conclusion, ”he said.

It is possible that a genetic mutation, that is, a small difference, neither good nor bad, could influence physical characteristics or susceptibility to certain diseases or disorders. This is something that can happen to one twin and now to the other.

Interestingly, given the genetic differences they found to be important, calling them identical twins may not be enough anymore and experts say they now call them monozygotic twins more than anything.

A psychologist who studies twins at California State University Fullerton, Nancy Segal (who was not in the most recent study), believes this new research is “heroic and truly meaningful.”

Study says identical twins may not be so identical after all

To increase the degree of innovation of this new information for science, this new research was able to examine the genetic mutations that occur in two different types of cells: those inherited by the person’s child and those present in a person’s child. only Gemini.

“This will force scientists to refine our thinking about the influences of genetics and the environment,” she said. “The twins are very similar, but it’s not a perfect resemblance.”

Identical twins are not always genetically identical, new study finds

Identical twins come from a single fertilized egg, or zygote.
In any embryo, cell division can lead to mutations, but this type of genetic difference has not been measured before between identical twins.

In a four-year study, a team of Icelandic researchers from DeCode Genetics, a biopharmaceutical company in Reykjavík, found that monozygotic or identical twins had genetic differences that begin in the early stages of embryonic development.

Scientists sequenced the genomes of 387 pairs of identical twins and their parents, spouses and children to track the divergence of mutations. The authors found that the twins differed on average by 5.2 initial developmental mutations.

In about 15% of twin pairs, one sibling carried a large number of these mutations that the other twin did not.

A genetic mutation is a mistake or change in DNA. A mutation occurs when the sequence of the genetic code breaks or changes in some way. Although most mutations are harmless, some can be serious and lead to diseases like cancer. Mutations can also affect physical attributes like hair color.

This is not the first study to suggest differences between so-called identical twins. An article published in The American Journal of Human Genetics in 2008 revealed some genetic differences between the brothers. However, the new research goes further, including DNA from the extended family.

Genetic differences
Some of the research subjects revealed surprising differences, study co-author Kari Stefansson told CNN.

“We found a pair of identical twins in which a mutation was found in every cell in one’s body, but was not present in the other twin. Then we found twins in which a mutation was found in all cells of the twin body, but in only 20% of each other’s cells, ”said Stefansson, the founder and CEO of DeCode Genetics, a subsidiary of US pharmaceutical company Amgen.

The implications of this are significant, Stefansson said, because the research led the team to conclude that “the role of genetic factors” in shaping the differences seen between monozygotic twins “has been underestimated.”
He acknowledged that science and society in general are fascinated by identical twins, adding: “There is something magical about the connection between identical twins.
However, her team’s research is more about what divides them than what unites them.

“Imagine you have identical twins who are raised separately. If one of them develops autism, the classic interpretation is that it is due to environmental factors. But our work shows that before concluding that this is caused by the environment, you have to sequence the genome of the twins to find out what could be responsible for autism, ”Stefansson said.
The “divergence of mutations,” he told CNN, could be responsible for a series of “devastating childhood illnesses,” such as severe epilepsy and a series of metabolic disorders.

We can’t wait to see what new research emerges on twins in the future!



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