Only six days will have separated the death of Grichka Bogdanoff from that of her twin Igor, who died Monday January 3 at the age of 72. Chance or genetic determinism? Here is what science knows today about monozygotic brothers.
- Known for hosting the science fiction show “Time X”, Igor and Grichka Bogdanoff were killed by Covid-19.
- They weren’t vaccinated.
Unlike fraternal twins, monozygotic brothers or sisters come from the division of a single fertilized egg.
They don’t always get along
The Bogdanov brothers were close, but identical twins don’t necessarily get along. “Even if the image of a perfect relationship between twins is often widespread, it is not uncommon, far from it, to see a disagreement from childhood. In some couples, a relationship of “dominant” and ” dominated” is set up according to the activities and the context”, explains psychologist Claire Lewandowski. Thus, the twin sisters Marine and Océane El Himer, both stars of reality TV, have had a stormy relationship in front of the cameras for many years. “The behavior of the entourage is not there for nothing, in particular when it emphasizes the comparison in the academic success, the sport or the friends”, says Claire Lewandowski.
They have the same eating habits
In contrast, monozygotic twins generally like to eat the same thing, as demonstrated recently researchers from King’s College London (a feature that is not found in fraternal twins, editor’s note).
They don’t have the same health issues
Beyond eating habits, identical twins do not necessarily have the same care pathways. Thus, from pregnancy, the place they occupy in the uterus means that identical twins can be born with different weights and pathologies. In the same idea, a study demonstrated that if a twin sister monozygous smokes regularly and the other does not, the first will have a lower bone density than the second.
They have small genetic differences
Although very similar in many ways, identical twins are not exactly the same biologically either. According to a recent research, monozygotic brothers accumulate an average of 5.2 genetic differences at birth. “About 15% of identical twin pairs have even more, with some as high as 100”, specify the authors.
They can give each other their skin
Last peculiarity of identical twins: they can give each other their skin if it is damaged. In 2017, the teams of Pr Maurice Mimoun and Pr Alexandre Mebazaan succeeded an almost total skin graft between two monozygotic brothers. The patient Franck Dufourmantelle had been burned to 95% following the explosion of a container at his workplace.
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