The question of whether we had a twin brother (even if he was lost in the womb) has an answer and it is in our (epi) genetics
Even if it looks like a lie, our understanding of why some deliveries are twins hasn’t changed much in the last couple of centuries. Of course, we now know that identical twins arise because the zygote (that is, the fertilized egg) divides into two embryos that share exactly the same genes. But I’m not talking about that “why”, I’m talking about something more basic: the reason why this division takes place.
So much so that, as we have not been able to find any “genetic minimum common” in all of them, the consensus among experts has been to randomly “blame” all of this. Regrettably. Because, although there are only around 2% of twin deliveries, it is estimated that 12% of pregnancies are multiples (but the embryos are lost during pregnancy). That means that even though we know that twins have specific medical problems, the vast majority of them don’t even know they are.
And, until now, there was no way to know. But, a team of researchers from the Vrije Universiteit in Amsterdam wondered if it was possible that we had not ruled out everything possible. What if there was something in the genome that until now had remained unidentified?
Thus begins to unravel a scientific mystery and a personal enogma
The team selected 924 homozygous twins and 1033 twins worldwide to analyze its genome in detail and search among its letters for some type of factors that could be behind the activation (or deactivation) of the mechanism that triggered the division of the zygote. And now, just published in ‘Nature Communications’, we have some results.
Up to 834 genome points appear to share the world’s identical twins. Thanks to them, for example, the authors can tell (with 80% reliability) if a person is an identical twin or not. Even in cases where the twin was lost in utero or had been separated at birth. In this way, the study does not close the debate on why there are identical twins, but it opens the playing field.
And it is that, although it has not been demonstrated that these “genetic marks” are the cause of the process; although very possibly they are a consequence of it: this study allows us to open the number of people to study, improve medical care and, hopefully, better understand what is behind this apparent chance.
Image | Sharon Mccutcheon