Genetic differences between identical twins can start very early in early development, according to a study Thursday that researchers said influences how these sisters help scientists to influence nature against getting nurtured.
An identity pair – or monozygotic – comes from one fertilized egg that splits into two halves.
They are important research topics because they are thought to have few genetic differences.
This means that when physical or behavioral differences arise, environmental factors are considered to be to blame.
But the new research, published in the journal The genetics of nature, suggesting that the role of genetic factors in shaping these differences has not been diminished.
“The classic model is to use an identical pair to help you differentiate the impact of genetics versus environment in disease analysis,” said Kari Stefansson, head of genetics at deCODE Iceland, a subgroup of US pharma company Amgen.
“So if you take an identical couple taken apart and one of them develops autism, the classic explanation is that that’s the cause of the environment.”
“But that’s a very dangerous decision,” he told AFP, adding that there is a possibility that the disease could be the result of an early genetic mutation that occurred in one of the couple but not in the other.
Stefansson and his team sequenced the genomes of 387 identical pairs of twins and their parents, spouses, and children to track genetic mutations.
They measured mutations that occur during embryonic growth and found that identical twins are different with an average of 5.2 early developmental mutations.
In 15 percent of couples, the number of relative bouts is higher.
When mutation occurs in the first few weeks of initial development, it would be expected to be widespread both in a person’s cells and in their progenitor cells.
In one of the pairs of twins studied, for example, a mutation was present in all cells in the body of one sister – meaning that it occurred very early in development – but not at all. the other couple.
Stefansson, out of the first mass that would go on to create the individuals, said, “one of the twins is made up of the descendants of the cell where the individual took place. change and nothing else “, while the other did not.
“These mutations are interesting because they allow you to start exploring the way a connection happens.”
Given the genetic differences found, the exact term could be misleading to describe the sisters.
“I’m more likely to call them a monozygotic couple today than they are their counterparts,” Stefansson said.
© Agence France-Presse