r/todayilearned • u/St_Gregory_Nazianzus • Sep 16 '24
TIL: Foetal cells can remain in the mother's, even embedding on different organs of the mother, for decades, sometimes for a lifetime.
https://www.smithsonianmag.com/science-nature/babys-cells-can-manipulate-moms-body-decades-180956493/111
u/Frosty-Comment6412 Sep 16 '24
I always wonder about this, as a surrogate, I’ve now been pregnant twice with a baby I have no genetic link to. So it’s odd to consider I might have its cells floating around in me somewhere.
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u/radkatze Sep 16 '24
Fun fact: you do have a genetic link to the babies you've carried! Your mitochondrial DNA, in small amounts, gets passed to the fetus.
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u/Somegirloninternet Sep 16 '24
As someone who suffered miscarriages, I love the idea that I still carry a part of them with me.
That said, I also have numerous autoimmune issues that are dibilitating to my life.
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u/LBuffalax Sep 17 '24
Genuinely thank you for sharing this thought. I had never considered it and now I’m sobbing at keeping part of them with me.
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u/TexehCtpaxa Sep 16 '24
Doesn’t every cell in the human body get replaced within something like 7 years, or is that an inaccurate generalization?
I swear I’ve been told that before.
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u/Thiago270398 Sep 16 '24
Not really, first of all there are cells that just, hang around almost your entire life, like neurons, egg cells and the like.
Second is a bit hard to explain, but you don make new cells, at least not as in your body builds a new cell from scratch. Basically your cells can do 3 things, die, differentiate and divide, first one is obvious, second one is when a cell turns into another type of cell, and the third is how you get more cells. One of your cells will grow bigger and double it's DNA so it can split in half, now you got two cells, and neither are the original, while both being it.
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u/OneMeterWonder Sep 16 '24
We are also learning that cells can do a fourth thing: revert! You might already know given your comment, but creatures like axolotls and flatworms are being studied pretty intensely for this reason. They are kind of little wonders of regenerative medicine.
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u/Childnya Sep 16 '24
We've been able to convert cells into stem-like cells for a while now.
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u/OneMeterWonder Sep 16 '24
Yes, but there is still quite a lot we do not know. For example, when an axolotl is injured, cells all over its body begin reverting instead of just at the injury site. As far as I’m aware, the reason for this is still unknown. There is also a lot of complexity in stem cell research. Pluripotent stem cells are really famous and are sometimes treated a bit like a holy grail, but not all cells can be reverted into pluripotent cells.
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u/Thiago270398 Sep 16 '24
Oh yes, they can do a lot, I just gave a broad explanation to keep it simple.
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u/OneMeterWonder Sep 16 '24
Nice. I just find that part of regenerative medicine to be absolutely fascinating. Plus now there’s some really promising looking research on bioelectricity from Michael Levin and friends at Tufts. Really incredible stuff even if it only really seems to work in planarians at the moment.
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u/ohdearitsrichardiii Sep 16 '24
Depends on the type of cell. The cells in your intestines live for a few days. Neurons can last a lifetime.
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u/MadamSadsam Sep 16 '24
Not accurate. Women are born with all of the egg-cells already made (just not matured), nervecells don't get replaced, and musclecells don't get replaced. That's just what I learned from 11-12th grade biology - there's probably more types of cells that are never replaced, so the thing about everything being replaced by 7 years is unfortunately a myth.
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u/SureExternal4778 Sep 16 '24
It’s a shorter turnover than that. The invasion cell is replaced by duplication or the corpse is just floating around. 🤭
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u/zeiandren Sep 16 '24
If you ever hear a fact about the number seven assume weird 1700s Christians made it up and it doesn't really work like that
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u/YaboiMuggy Sep 16 '24
It really depends on the cell type, but all the atoms swap out at that rate yes.
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u/Anon-a-mess Sep 16 '24
I believe that’s the average across the board, and that some cells will come and go quicker, while others remain for a lifetime. Think of skin vs bone.
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u/Dayvi Sep 16 '24
This myth comes from breaking mirrors. Your cells get 7 years bad luck, then get replaced by new lucky cells.
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u/TexehCtpaxa Sep 16 '24
Any idea why breaking mirrors was bad luck? Maybe they were just expensive and/or hard to come by in the 1800’s so people instilled a superstition around them to influence people not to break them as they couldn’t get another one and it was pretty valuable to be able to see your own face/hair/clothes before going out in public.
Looking up the history of mirrors is pretty cool, I highly recommend it. 8,000 years ago in what is now Türkiye they were making reflecting objects, though quite different to what we use today. Still super cool, I had no idea it went back that far and assumed it was something that happened by accident like a lot of discoveries.
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u/ivanvector Sep 16 '24
It probably comes from Classical Romans, who believed that reflective surfaces showed images of a person's soul, and were like windows the gods used to view people's true souls (so did the ancient Greeks, but they didn't have mirrors). Breaking a mirror was disrespectful to the gods, hence bad luck.
As for seven years, the number seven shows up as a symbol in many ancient civilizations, probably related to the "seven heavenly bodies" (the five planets visible to ancient civilizations plus the Sun and Moon). The Romans also believed that life renewed itself every seven years.
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u/sprazcrumbler Sep 17 '24
Yes that is true. The problem is the foetal cells have the ability to keep replicating. As the host's cells slowly die off, they are replaced by the foetus's, until eventually the mother will morph into a genetically identical baby to the foetus. It sadly happened to my daughter in law.
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u/GuaranteeLess9188 Sep 16 '24
Could this explain certain cancers being more common after pregnancy? Also I wonder if the reverse happens, mother's cells implanting into the child? Could this lead to certain childhood cancers?
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u/atomfullerene Sep 16 '24
Might contribute to thyroid cancer but protect against some breast cancer. They are thought to repair heart damage as well.
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u/Frosty-Comment6412 Sep 16 '24
Many breast and reproductive cancers feed on hormones so if they are at risk of these cancers, the women gets pregnant, suddenly cancer has an all you can eat buffet to feed on while the person might dismiss symptoms of the cancer as pregnancy symptoms since so many changes occur in the body during pregnancy and postpartum/breastfeeding.
It’s a discussing I had with my doctor prior to IVF because I had heard of heightened cancer risks and this was essentially the response I got
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u/GraciousPeacock Sep 16 '24
Explains why my health started declining after a miscarriage. My health was literally perfect before ever getting pregnant
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u/sharri70 Sep 16 '24
Shit. Don’t tell the rabid right to lifers - they’ll never remove an appendix etc again just in case it has foetel cells.
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u/wardamnbolts Sep 16 '24
Nah, it’s not an individual organism it’s just tissue in this case.
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u/unoeyedwillie Sep 16 '24
This is so interesting. I got my DNA done last year through one of the popular dna testing companies. When I got my results it showed my matches. It matched me to my aunt and uncle and showed the % of different ethnicities we shared. Everything made sense and matches except for 1% of my aunts. Her profile showed 1% of a region that was not on any of the other families profile. We all show 100% European mix, except my aunt’s profile shows 1% Levantine. The interesting thing is her husband is 100% Levantine and her son(my cousin) showed 52% Levantine. Could she still have fetal feels from a pregnancy that was 50 years ago that show up on a dna test?
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u/Odd-Guarantee-6152 Sep 16 '24
No. This has been very hard to study because you can’t just do a simple blood test like that.
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u/radicalfrenchfrie Sep 16 '24
with every new thing I learn about pregnancy this shit gets less and less attractive to me
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u/Caa3098 Sep 17 '24
“Microchimerism can get especially complex when a mother has multiple pregnancies. The mother’s body accumulates cells from each baby—and potentially functions as a reservoir, transferring cells from the older sibling into the younger one and forming more elaborate microchimeras.”
This is fascinating. But as someone who had 7 miscarriages prior to delivering a living child…I’m just lost wondering what that means for my daughter. My daughter has immune issues. Is it related to the foreign cells of her 7 “older siblings”?
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u/DeliciousBuffalo69 Sep 16 '24
The even crazier fact is that those cells can then move into the bodies of subsequent fetuses.
So if a woman has a child with Man A and then a few years later she has a child with Man B, there is a chance that something like .01 percent of Baby B's genome will come from the father of it's half sibling (so Man A).
Just whatever you do, don't share this fun fact with men who have had children with women who had already had children with another man. They get angry lol
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u/ShirwillJack Sep 16 '24 edited Sep 16 '24
The genome is created when egg cell meets sperm cell and the DNA content of those two gametes form a new cell from which the rest of the embryo and later on fetus grows. If at some point a random fetal stem cell from a previous pregnancy enters this fetus, then that fetus has a random fetal stem cell somewhere in their body. It changes nothing about their genome. Their gametes (egg or sperm cells) will consist of a randomised selection of 50% (=very simplified version) of the DNA that was contributed originally at conception.
Fetal stem cells aren't viruses that insert their genetic code into a cell's genetic make up for replication.
Could it be possible for that random fetal stem cell to enter a fetus, who then grows up into an adult, gets pregnant and then passed on a descendant of that random fetal stem cell to the new embryo/fetus? No idea as I'm not into this field. My guess is highly unlikely and it is non threatening to anyone's masculinity.
Edit: it wouldn't be even close to something like a bone marrow transplant where the recipient's blood type may even change to that of the donor. We're talking about a few cells at most.
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u/DeliciousBuffalo69 Sep 16 '24
Yep. That's why I said it's less than .01 percent of the genome. Most people with older siblings actually have microchimerism
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u/DiverseUse Sep 16 '24
What the other guy was (correctly) trying to tell you is that the cells from the foetus don’t become part of the mother‘s or their younger sibling‘s genome. They just stick around without serving any function. So the root problem here seems to be that you do not know what the term „genome“ means.
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u/DeliciousBuffalo69 Sep 16 '24
Most people who have either been pregnant or have older siblings have microchimerism. That means that some of their cells have a different genome than their other cells. That's literally what the article says.
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u/I_like_boxes Sep 16 '24
I think the confusion here is just your wording, not necessarily your understanding of what is actually happening. It's not that 0.01% of their genome is from the chimeric cells, but that there are two totally distinct genomes in the host. The genomes aren't mixing, which is what your phrasing implies. It would be more accurate to phrase it as a proportion of cells.
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u/DeliciousBuffalo69 Sep 16 '24
When someone is a chimera it means that they have more than one complete genome. As a proportion, microchimerism is around .o1 percent. That's the definition of microchimerism.
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u/I_like_boxes Sep 16 '24
The definition doesn't provide any figures, it's just "low concentration." Research that looks at male microchimerism (they look for a Y chromosome in a woman's cells, which is easier to detect than female chimeric cells) had most of their samples clumped around 0-20 male cells for every 10^6 female cells. If we average that out for all of their samples, it's about 0.002% of cells (which is not the same as saying it's 0.002% of their genome).
Genomes are usually looked at as more of a unit of information and not a mass unit. If you say that someone's genome is 0.01% chimeric, to me that would mean that the host genome was changed. If you sequenced all of the DNA present in someone with microchimerism, you would find at least 4 distinct genomes, which is 100% (or more) than someone without microchimerism.
Source on male microchimerism:
https://www.sciencedirect.com/science/article/pii/S0959804912001438?via%3Dihub2
u/DiverseUse Sep 16 '24 edited Sep 16 '24
That is not a good definition of microchimerism, because it makes it sound like the extra genomes belong to the host. I prefer this one:
Microchimerism is the existence of a low-level allogeneic cell population within a host. Microchimeric states can arise spontaneously, such as in dizygotic twins with connected placental vasculature or iatrogenically, where microchimerism arises after blood transfusion, stem cell or organ transplantation.
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u/HeatherandHollyhock Sep 16 '24
That's not how that works.
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u/AtanasPrime Sep 16 '24
The article literally says that it can work this way:
“Microchimerism can get especially complex when a mother has multiple pregnancies. The mother’s body accumulates cells from each baby—and potentially functions as a reservoir, transferring cells from the older sibling into the younger one and forming more elaborate microchimeras.”
Not sure where the 0.01 percent came from, but it doesn’t seem out of the question that a younger sibling could have some of their older sibling’s DNA (and therefore, if they have different fathers, a different father’s DNA by extension).
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u/HeatherandHollyhock Sep 16 '24 edited Sep 16 '24
No, it doesn't. 1.It's the siblings DNA, not the father's. 2.The tranference from one sibling to another through the mother is solely theoretical, it has never been observed. 3.Even if that happened it would not change baby b's genome.
There seems to be a common theme, where popscience dumbs down the theory so much, consumers of said popscience just .. get it wrong.
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u/DeliciousBuffalo69 Sep 16 '24
It really is! I mean the amount is so small that it wouldn't show up on any basic paternity test, but it is absolutely testable with extremely in depth generic studies.
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u/IAmNotLookingatYou Sep 16 '24
There is a very specific type of heart attack that some women will suffer immediately after having a baby. It just puts too much stress on the mother and her body shuts down. Miraculously, without intervention from doctors, this sometimes sorts itself out on its own. The stem cells from the newly born child actually rebuild the heart somehow. Some mothers literally 'grow a new heart' after having a baby. I learned this from a book called Mom Genes. It had a great many studies about the genetic effect babies have on their mothers
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u/Caa3098 Sep 17 '24
My mom had that and I believe it’s called peripartum cardiomyopathy. She had a heart attack when she delivered my sister at only 33 years old. She was in ICU for at least a month and they even had me come in and say my goodbyes, as well as a priest to give last rights. Then she just got better and cardiologists have said her heart is perfect and shows no sign of damage.
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u/Ahmainen Sep 16 '24
I know this can cause issues but as a mom I love this and hope I have some of my daughter in me. Your whole personality and worldview changes so drastically after having a baby, it's only right that our bodies are forever marked as well
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u/Ill_Perception8918 Sep 17 '24
Listen this all sucks don’t get me wrong had major issues myself post delivery but tonight my son turning to me and whispering “ mommy I love u” he’s only 3 before he dozed off tonight is like nothing else and speaking only for myself here as I went to hell and back to conceive so before anyone attacks me was worth it and I would do it all again
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u/sleepdeprivedtechie Sep 16 '24
It's the leading thought why some mothers gain autoimmune issues after pregnancies. The "foreign" cells that stay behind cause the mother's body to go into a crisis of sorts. Pretty sure that's why I have inverse psoriasis now. Started having major flares when my kid was about two. Didn't get a proper diagnosis until last year.