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This may seem incredible, and yet: an American woman gave birth to children who do not carry her DNA, without being a surrogate mother. The reason: her twin sister’s DNA was present in her, a “vanishing twin” who passed on her genetic material to her own children. The explanations of this phenomenon, called microchimerism, are published in the book by scientific journalist Lise Barnéoud, “Les Cells Buissonières” published by Premier Parallel Editions.
Fetal microchimerism. It’s a name that may not mean anything to you. It hides a somewhat particular phenomenon, which concerns our DNA. A phenomenon at the heart of the book by scientist Lise Barnéoud, “Les Cells Buissonières”, published on September 21.
The story of an American woman who does not share the DNA of two of her children
In The truant cells, science journalist Lise Barnéoud recounts specific scientific cases about this phenomenon that is microchimerism. There is the story of Lydia Fairchild, whose maternity tests necessary to obtain social assistance in the United States reveal that, from a genetic point of view, she is not the mother of her two children.
Or that of the American Karen Keegan, mother of three children, who, following genetic tests carried out with a view to a kidney transplant, was told by doctors: “Two of your sons do not match your DNA”. How to explain this? In fact, Karen Keegan carries the DNA of an unborn twin sister, a so-called “vanishing” twin sister whose genetic material was passed on to her own children.
Microchimerism is explained by the fact that, in some people, the genetic material contained in our cells does not only come from the initial egg cell, at the time of conception. Our body is made up of hundreds of billions of cells, some of which could sometimes contain DNA other than ours. They come to us from our mother, through the placenta, from a “vanishing” brother or sister, sometimes from elsewhere…
For Karen Keegan, her mother’s pregnancy began with two fetuses but only one came to term, the other being called a “vanishing twin.” A case which would affect 10 to 30% of births. A trace of this missing brother or sister can persist in the body of their twin. Concretely, its cells can insert into the other and become parts of certain of its organs. In Karen Keegan’s case, doctors believe the two fetuses merged since some of her eggs contain the genetic information of her sister who was never born.
These cells from another organism can be found everywhere, in the blood, but also in other organs, in small quantities. Organ transplants or blood transfusions can also cause microchimerism phenomena.
A mystery to science, for now
If the phenomenon is indeed recognized, science is only at the beginning of understanding this phenomenon. In her book, journalist Lise Barnéoud investigates and reports the first scientific advances on the subject.
While describing microchimerism, she also reports the consequences it causes: children not sharing the same DNA as their mother, therefore but more serious: a rapist who is not arrested because the DNA collected from the victim matches to that of his brother already in prison (the mechanism at play was then a bone marrow transplant between the two brothers). Or a woman who develops metastases following a kidney transplant and is cured of cancer once the graft is removed… So many mysteries which will require years of research before being able to shed light on their precise explanation.
A true scientific investigation and through very unique cases, a fascinating dive into the heart of an astonishing field full of mysteries but also hope from a therapeutic point of view.