Oct 01, 2021 21:00:00

You can check if you have 'twin brothers and sisters who disappeared before you were born' by checking your DNA.

Monozygotic twins are derived from egg cells that divide to produce two embryos. In some cases, one of these two embryos disappears during development, in which case only one baby will be born. This phenomenon

is called 'vanishing twin ', but according to the latest research, the DNA contains information to confirm whether the embryo was born as an identical twin, and it disappears by itself. It is possible to confirm whether there were twin brothers and sisters.

Identical twins carry a persistent epigenetic signature of early genome programming | Nature Communications
https://www.nature.com/articles/s41467-021-25583-7

Did you share the womb with a'vanishing twin'? The answer may be written in your DNA. | Live Science
https://www.livescience.com/identical-twins-unique-epigenetic-signature

In a recent paper published in the scientific journal Nature Communications on Tuesday, September 28, 2021, researchers focus on the epigenetic landmarks found in twin DNA. Epigenetics is a factor that allows a gene to be turned on and off without changing the underlying DNA sequence. For example, the methyl group , which is one of epigenetics, attaches to specific genes like sticky notes, preventing cells from reading those genes and effectively turning off the genes.

The study found that the DNA of identical twins had a 'characteristic pattern of sticky methyl groups.' It was also revealed that the 'characteristic pattern of sticky methyl groups' spans 834 genes and is used to distinguish identical twins from two, dizygotic and non-twin. I have.

In addition, the research team has also succeeded in developing a computer algorithm that can reliably identify identical twins based solely on the location of the methyl group throughout the DNA. By this, in theory, it is possible to confirm whether or not there is a brother or sister who disappeared in the vanishing twin. However, this study has not verified this vanishing twin.

Live Science, a scientific media outlet, interviews Robert Waterland, a pediatrician and professor of genetics at Baylor College of Medicine, as a comment from an expert not involved in the study. Regarding the 'characteristic pattern of sticky methyl groups' discovered in this paper, Waterland said, 'This is a kind of'molecule that remained during the early embryonic development process in identical twins. It ’s a scar. ”

Methyl group-coated genes play a variety of roles in cell development, growth, and adhesion. Simply put, it helps cells stick to each other. However, 'it is unclear from the results of the study how methylation genes affect the growth, development and health of identical twins,' said Waterland.

International Journal of Fertility and Sterility reported in 1990

report According to the estimated 12% of the human pregnancy but begins as a multiple pregnancy, the probability that a child will be born as more twins seems less than 2%. In other words, the remaining 10% are so-called vanishing twins. It is generally said that there are more fraternal twins than identical twins.

Dizygotic twins are bestowed by fertilizing two eggs. Therefore, there is evidence that heredity affects dizygotic twins. For example, it has been suggested that dizygotic twins may be given to the family, and research results have been published showing that genes related to excessive ovulation are involved.

On the other hand, the proportion of identical twins born is constant worldwide, and it is calculated that 3 to 4 out of 1000 are born. Therefore, it has been thought that identical twins are not caused by heredity. The question then becomes, 'What causes identical twins?'

Jenny van Donggen, lead author of a paper reporting on the 'characteristic pattern of sticky methyl groups' present in the DNA of identical twins and an assistant professor of bioethics at the Free University of Amsterdam He said he conducted this study to better understand how identical twins develop.

In investigating 'what causes identical twins?', The research team wondered if the methyl groups that make up DNA might have the secret. Methyl groups play a role in controlling embryonic development in the early stages. Also, thanks to a special protein called methyltransferase , it becomes clear that the methyl groups added to the developing DNA continue to be copied while the cells continue to divide and remain in adulthood. I did. This is the 'characteristic pattern of sticky methyl groups'.

The research team has analyzed blood or DNA samples from 6000 identical and dizygotic twins, as well as non-twin, and published a paper. In addition, the dataset on which the analytical study was based also includes DNA samples collected at multiple times, so the 'characteristic pattern of sticky methyl groups' is stable over time. It is also clear that you can check it.

In this research study, it has not been clarified what kind of effect the 'characteristic pattern of sticky methyl groups' will have on the human body. Therefore, the research team is planning to use experimental animal cells and human cells to study what kind of effect it will have.