You are part of your mum and she is part of you, literally!

There is a special bond between mothers and their children, but what if I told you that part of them literally lives within their children?

Some cells within your body are not yours! They were shared with you by your mother during pregnancy, and during that time you shared some cells with her too. There is an exchange of cells, which cross through the placenta, in both directions.

We are all chimeras … sort of

This phenomenon is called microchimerism: when an individual presents both its own cells and also a small number of cells that came from a genetically different organism.

The name is derived from the chimera, a mythological creature made of parts of a lioness, a goat and a serpent.

The Chimera of Arezzo, c. 400 BC. Image by Carole Raddato on Wikimedia Commons.

This exchange of cells can naturally occur during pregnancy and it was first described in 1979 by L. A. Herzenberg. The idea was hard to recognize, as often happens in the scientific community, but nowadays is an accepted phenomenon.

How was it discovered?

While working on a test aimed to help detecting pregnancy problems as early as possible, Herzenberg and colleagues discovered male fetal cells within blood samples of a group of mothers!
They used a technique called flow cytometry that allows the researchers to manipulate and sort cells one by one.

Depending on their particular role cells can be identified by looking for specific proteins present in their surface. Proteins are one of the essential building blocks of life, and their functions can be found in any cellular activity like movement or how cells react to the world outside them.

Some of this surface proteins are only shown by a certain group of cells, so if you can identify the proteins you can identify what kind of cell is.

This discovery was later confirmed by Dr. Diana Bianchi in 1996, using a similar approach to identify fetal cells from blood samples, but now working with women who had previously given birth to a boy and that were not pregnant during the study.

Surprisingly they were able to detect male fetal cells even in women who had given birth up to 27 years earlier!

A literal connection

If you have an older sibling then I have good (or terrible) news for you. As the cells a mother can receive from their first child can continue living within them for years, there is a chance in which some of those cells are actually shared from the mother to her second child. You might have a few of your older sibling’s cells within your body!


Family silhouette shadows. Image by Carissa Rogers on Wikimedia Commons.

Touching their heart

As incredible as it might sound fetal cells can travel to the mother heart and be part of cardiac injury recovery in women who experienced heart failure during pregnancy.

I can bet you won’t see your mother and siblings as before. Turns out we all are chimeras.

8 Responses to “You are part of your mum and she is part of you, literally!”

  1. Marco M. says:

    Thank you, Daniel! Yes, the last part is my favourite too! It is amazing how this exchange of cells takes place even though microchimerism has also been involved in negative outputs too but is not yet clear if the relationship is causative or not.
    I think is very likely you carry a few of their cells!

  2. Marco M. says:

    Thank you, Iman! Honestly, I don’t know if cancer cells would be able to become microchimeric…There are plenty of questions yet to solve and it seems like an unknown mechanism of the immune system is involved in how microchimeric cells managed to be “accepted” by the host so I would bet that any cancer cell would not be allowed!

  3. Marco M. says:

    Thank you, Jasmine! I am glad the science is clear. And yes microchimerism can be a little bit horrifying but it also shows how mysterious nature can be!

  4. Marco M. says:

    Yes!, microchimerism changed the way I see families and individuals

  5. Daniel Hutchinson says:

    This is super cool Marco
    I really liked how well all the writing flowed and the bit at the end was super sweet (definitely the coolest part).
    Although I really hope I didn’t get any cells from my sisters, that would be terrible news. Do you think 5 years is enough that I’m unlikely to have gotten any of their cells?

  6. Iman Taleb says:

    This is one awesome post! I am a mother myself and reading this post made me even more attached to my kids! On the other hand, it is kind of worrying somehow. It left me wondering if a mother had cancer cells that hadn’t turned into a detectable tumor while pregnant, could these cells be passe on to her baby this way?! scary!

  7. Jasmine Rhodes says:

    Marco! This idea freaks me out, but the post is great! I was able to understand the science, which is way out of my field. An engaging, and informative (even if slightly horrifying) post 🙂

  8. Zoe Canestra says:

    Woah this is a super spooky thought! Sharing is caring takes on a whole different meaning lol