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Studies have found that identical twins are not 100% identical after all



Researchers say that genetic differences between identical twins can begin very early in embryonic development. Researchers say this has something to do with how these brothers and sisters help scientists understand the effects of nature and nurturing.

Identical twins or identical twins come from a single fertilized egg, which is divided into two.

They are important research topics because they are considered to have minimal genetic differences.

This means that when physical or behavioral differences occur, they may be caused by environmental factors.

But this new research was published in the journal Natural genetics, Indicating that the role of genetic factors in shaping these differences is underestimated.

Kari Stefansson, head of genetics at deCODE Iceland, a subsidiary of the American pharmaceutical company Amgen, said: “The classic model is to use identical twins to help you distinguish the effects of genetics and environment on disease analysis. “

“So if you separate identical twins and one of them develops autism, the classic explanation is due to the environment.”

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He told AFP: “But this is a very dangerous conclusion.” He added that the disease is probably due to early genetic mutations in one of the twins, while the other pair did not.

Stefansson and his team sequenced the genomes of 387 pairs of identical twins and their parents, spouses, and children to track genetic mutations.

They measured the mutations that occurred during embryonic growth and found that the average early developmental mutations of identical twins differed by 5.2.

In 15% of twins, the number of divergent mutations is higher.

When the mutation occurs in the first few weeks of embryonic development, it is expected to spread widely in individual cells and their progeny cells.

For example, in a pair of twins in the study, mutations are present in all cells in one sibling, which means that it is likely to occur early in development, but not at all in the other twin.

Stefanson said that in the initial mass that continues to form an individual, “one of the twins is made up of the offspring of the mutated cell, and nothing else.”

“These mutations are interesting because they allow you to start exploring how twins occur.”

Given the genetic differences found, the term “same” may be misleading to describe siblings.

Stefanson said: “Today, I prefer to call them monozygotic twins rather than identical twins.”

©AFP


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