Human Chimeras / Chimaeras

[Anonymous]

Sons I gave birth to are 'unrelated' to me
By Roger Highfield
(Filed: 13/11/2003)


One human chimera came to light when a 52-year-old woman demanded an explanation from doctors after tests showed that two of her three grown-up sons were biologically unrelated to her.

Although the woman, "Jane", conceived them naturally with her husband, tests to see if she could donate a kidney suggested that somehow she had given birth to somebody else's children.

A study in the New England Journal of Medicine by Dr Margot Kruskall, of the Beth Israel Deaconess Medical Centre in Boston, Massachusetts, showed that Jane is a chimera, a mixture of two individuals - non-identical twin sisters - whose cells intermingled in the womb and grew into a single body.

Dr Kruskall believes the most likely explanation is that Jane's mother conceived non-identical twin girls, who fused at an early stage of the pregnancy to form a single embryo, according to a report published today in New Scientist.

For some reason, cells from only one twin dominate in Jane's blood - used for tissue-typing. In her other tissues, however, including her ovaries, cells of both twins live amicably alongside each other, hence the apparently impossible genetics of her three sons.

One son came from an egg derived from the twin whose cells dominate Jane's blood, while his brothers came from eggs derived from the other twin's cells.

Around 30 similar instances of chimerism have been reported, and there are probably many more who will never discover their unusual origins. Most chimeras probably go through life unaware of their unusual constitution.

Link: Source

Not that I know anything about science, but it almost sounds plausible. We have some very learned people in our midst, could someone tell me if this possible or just a slick news filler for a Friday?

 

[marion]

Interesting! I've heard of this before,someone being two people so to speak, how does she know which are 'her' sons and which her sister's? Which set of genes would belong to her conciousness?

 

[Anonymous]

Interesting question since one twin's DNA is in her blood and the other's is in her tissue (organs). I really couldn't say.

 

[gyrtrash]

So, some cells have one set of genes, others have the sisters?

That's so odd. Makes me wonder if there's anything we can learn from that for transplant patients. My mate who's had a liver transplant worries about the organ being rejected by his body cos it's got another person's cells.

I just thought - if our cells replace themselves every few years, how come his new liver carries on replacing themselves with another persons cells? Has his liver still got part of the other persons conciousness? Why can't his body programme the new cells to be his? If you grow new skin after injury, your body tells the cells to form your cells with your DNA. Any new cells in his liver will be new, not come from his old cells?

 

[marion]

Cause the liver cells renew themselves-thats why we get old and fall apart, our cells make mistakes over the years as they copy themselves over and over. The cells in the liver will renew themselves from themselves not from cells from other parts of the body.

 

[gyrtrash]

Does that mean every liver cell he had of his own would form a liver that would fail, eventually?

 

[marion]

Does that mean every liver cell he had of his own would form a liver that would fail, eventually?

If it was a genetic failure yeah.

 

[Cult_of_Mana]

Found another article about human chimeras. It's dated May 2002 so it isn't exactly new news. Absolutely fascinating nonetheless. See here. Also discusses 'mosaicism' which may have been the cause of John Merrick's 'elephant man' disease.

Edit: There is a big article in this weeks New Scientist too but doesn't seem to be available online (except for subscribers). I'm puzzled why it's taken over a year for this subject to make really big news. It throws what we know about immunology on it's head! :eek!!!!:

Embedded link is dead. The MIA article can be accessed via the Wayback Machine:

https://web.archive.org/web/20031001191531/https://www.nature.com/nsu/020429/020429-13.html

Here's the introductory text ...

Human genetics: Dual identities

Some people's blood contains cells from a sibling. Others are two individuals rolled into one. Yet more carry a distinct mutation in only parts of their bodies. Helen Pearson investigates chimaerism and mosaicism.

2 May 2002
HELEN PEARSON

This article is from the News Features section of the journal Nature.

Eight years ago in Britain, a boy was born who, genetically, was two people. He was formed when two eggs, fertilized by two different sperm, fused into one embryo inside his mother's womb.

He was an unremarkable baby. But as a toddler, doctors discovered that he was a hermaphrodite - what was originally diagnosed as an undescended testis turned out to be an ovary, a fallopian tube and part of a uterus. Further investigation revealed that some parts of his body were genetically female but the rest, which contained a different combination of his parents' genes, was male. ...

The boy, who was otherwise healthy, is one of only a handful of known true human chimaeras - people carrying tissues that originated in two separate embryos. More common are mosaics, who have patches of tissue that differ genetically from the rest of their body, thanks to a mutation or chromosomal anomaly that arose early in embryological development. ...

 

[intaglio]

What I find interesting about the New Scientist article is that they say that it is more common than originally thought. Mothers cells implant into the foetus etc. Thos has some dire consequences for DNA testing

 

[marion]

I first read about human chimeras many years ago- how it is possible to have two blood types/tissue types in one person so it isn't new science.
Mosaicism (where some parts express a dominant gene and other parts a carried recessive) turn up occasionally in the world of small animal breeding so must occur in humans, you can only tell with animals when the colour is affected and it can be quite striking e.g a siamese cat with mixed blue and seal points.

 

[OneWingedBird]

The New Scientist article was good, as you say, a pity it's not available online.

It ocurred to me that this has the potential to create some subtle and hitherto unknown intersex conditions.

 

[Cult_of_Mana]

What I find interesting about the New Scientist article is that they say that it is more common than originally thought. Mothers cells implant into the foetus etc. Thos has some dire consequences for DNA testing

Absolutely! Many of us could have two or more genomes present in our bodies. How is this going to affect forensic science? It should liven up evolution studies too.

This stuff just blows my mind. I'm in awe of biological processes.

 

[marion]

I can photocopy the article at work if anyone wants it.

 

[stonedog3]

whatever her "mother" status I do hope it doesn't badly alter her "mum" relationship with the kids :-(

Kath

 

[Onix_Martinez]

I can photocopy the article at work if anyone wants it.

I am interested, would really appreciate it if you took the time to copy it. Thanks.

 

[littleblackduck]

Mother child chimaera

I read an article some time ago about the sharing of cells between mothers and sons--apparently their bodies "take hostages" so to speak when the child is in the womb and as much as thirty or more years later, you could still be carrying cells that are genetically maternal.

This may have something to do with the immune system, since there is an elaborate mechanism which prevents the maternal body from treating the genetically different fetus as a foreign body to be destroyed.

In other words, we may be all a little bit chimaerical, at least on our mother's side.

Chimaerical cells and the anti-immune system may younger sons have more health problems (and if the research is reliable) why younger sons from multi-son families are (possibly) slightly more likely to be gay.

Quite a few of us must be chimaerical--who knows? Perhaps we have all swapped a few cells with our mothers, just to make it through the maternal immune defence system.

There is also a fairly large number of us who may be our own twin brothers and sisters. (I think this has also been proposed as a biological model of homosexuality, but more tentatively than most of the theories).

As for the woman in the article, if she gets really annoyed, she can honestly tell her sons "You're no blood of mine!" The real question is: Is she herself or is she really her twin sister?

 

[intaglio]

Re: Mother child chimaera

... As for the woman in the article, if she gets really annoyed, she can honestly tell her sons "You're no blood of mine!" The real question is: Is she herself or is she really her twin sister?

Nice one, LBD! I think she'd be in 2 minds about it.

 

[Mighty_Emperor]

Monday 6th March

The Twin Inside Me: Extraordinary People
21.00-22.00
five

Repeated on the same channel on Thursday 9th at 23.00-00.00

--------
five's article on the case:

The Twin Inside Me

It seems like every second chat show features a suspicious man demanding a DNA test to prove he is the father of his lady’s children. It’s not uncommon for a man to discover that his children do not share his genes. But what if, as a mother, you were informed that the children you had carried and given birth to were not, in fact, yours? No, this is not the plot of the latest Alien film; it’s Lydia Fairchild’s life. This is the amazing story of an American woman who found herself risking losing custody of her children after a routine DNA test gave a freakish, one-in-a-billion result.

Lydia had three children with her partner Jamie. Around the birth of the third, the couple separated. Alone, with no means of support, Lydia applied for welfare and was asked to submit DNA samples to prove that she, the children and Jamie were all related.

The results were mind-boggling. They confirmed that Jamie was the father but they stated categorically that Lydia was not the mother. Lydia couldn’t believe her eyes, but two further tests confirmed that Lydia’s DNA was completely unrelated. Unless Lydia could prove she was the mother, she would lose custody of her kids.

Astonishingly, Lydia was taken to court for fraud. The judge accused Lydia of claiming benefit for other people’s children, or being part of a surrogacy scam. The DNA sample was considered to be foolproof, while traditional evidence - such as hospital records of her births - was disregarded. Lydia’s life was falling apart; at four-months pregnant, she couldn’t even afford legal support. But her luck changed when she came across a lawyer with an interest in her circumstances.

Two thousand miles away, Karen Keegan had been through a similar ordeal. Aged 52, Karen needed a kidney transplant so her adult sons were DNA tested as potential donors. To her horror, though, Karen discovered that she shared no genetic material with her sons. Luckily for her, the authorities accepted that she was their mother. Lydia’s lawyer contacted Karen, hoping that she could help Lydia through this horrific experience; the two sides began to investigate this bizarre case.

A series of tests had shown that Karen was a ‘chimera’ - a term derived from the Greek mythological creature that was a mutation of more than one animal. Shortly after conception, the female egg that was to become Karen became fused with another female egg. As a result, the fused egg contained two entirely separate DNA blueprints which were combined in Karen. This means that, biologically, Karen is more than one person.

This situation is not as rare as we might think. In fact, most pregnancies begin as twins, with one embryo absorbing the other. Karen was actually lucky; if the second egg had fused with the first at the same time and been male, Karen would have become a hermaphrodite. If it fused later, when the eggs had started developing, she would have become one half of conjoined twins.

The evidence was put before the judge, who ordered samples to be taken from Lydia during childbirth. Again, these showed that there was no apparent DNA link between her and the newborn, who was obviously hers, thus proving the chimera theory.

This condition is receiving increasingly more publicity - it even recently featured in an episode of CSI. When the obvious culprit of a rape did not match the DNA left in his victim, investigations revealed that his blood contained different DNA to his semen. There was also a real-life case of a cyclist filling his veins with someone else’s blood in order to cheat a pre-competition DNA test, then claiming he had the chimera condition. It's gruesome, but true.

Lydia’s nightmare was almost over, and she and Jamie are now back together. But very little is still known as to why cells fuse to create chimeras in the first place. The condition is often dormant, not affecting people’s external appearance, and only picked up during hospital checks. Who knows how many chimeras are walking amongst us?

www.five.tv/programmes/extraordinarypeople/twininside/

--------------
It was also the key part of a CSI plot where they tracked a rapist down to a fmaily but couldn't pinpoint he actually criminal - turns out he was a chimera.

------------------
Wikipedia:

http://en.wikipedia.org/wiki/Chimera_%28genetics%29

 

[Leaferne]

There was a recent equine chimera case brought to light; will dig it up if anyone's interested.

 

[TheQuixote]

The Twin Inside Me: Extraordinary People

I saw this earlier and it was well weird and quite heart-wrenching in Lydia's case (see the quote in Emp's post). Unless you have presenting problems, anyone could be knocking around oblivious to the fact they have this condition.

What was also fascinating was the photos of the chequerboard-skin pigmentation that can sometimes occur. Quite dramatic and most unusual.

It was also the key part of a CSI plot where they tracked a rapist down to a fmaily but couldn't pinpoint he actually criminal - turns out he was a chimera.

I think it was the Harvard doctor in tonight's programme that mentioned that there maybe cases where DNA evidence may have let the victims of crime down, similar to this.

 

[Mighty_Emperor]

It was amazing - I didn't know about this until that CSI episode - which was Bloodlines:

www.csifiles.com/reviews/miami/bloodlines.shtml

Which I suspect is based on one of the cases shown in the documentary.

What amazed me was patterning on the skin - esp. the woman with a very clear chess board pattern. I was also saddened and amazed (in equal measure) by the baby who's right side appeared to be a black/swarthy male and her left side was a white female.

The implications for DNA profiling of crimes they (and CSI) highlighted was scary.

There was a recent equine chimera case brought to light; will dig it up if anyone's interested.

Sure go for it.

 

[Leaferne]

OK--now this was a forward of a forward (etc.) so I don't know who to credit as the author of the email.

Has anyone else read the brindle article in the QH Journal? I just got my AQHA Journal today and there is a fascinating article included on Dunbars Gold and Sharp One, both AQHA registered brindles. I am going to paraphrase the article, as it is extremely interesting, and basically, freaking cool!

To paraphrase the article, these two brindle horses were bred via shipped semen and produced a 2004 colt. When the a sample from the foal was sent in for DNA typing/parentage verification via UC Davis, the results came back twice saying that not only could Dunbars Gold not be the sire but that Sharp One could not be the dam. AQHA registrar asked US Davis to look into this more closely.

What they found was extremely interesting. They looked up Dunbars Golds prior DNA info and found that he had to be tested three times before they could establish his DNA type. At that time, they had also noted that his hair was quite unusual, looking like it had come from two separate animals. They got several mixed DNA results and finally requested a blood sample from the stallion that typed to one animal. Even stranger, Dunbars Gold had a DNA sex-linked markers consistent with a FEMALE with no Y chromosome found in the blood sample. (aside: Ok, that is WEIRD). He was retested, and some tests then resulted in male markers while others resulted in female. The researchers came to the conclusion that the stallion was a chimeric, which is an individual formed from two different cell lines. They believe that the stallion is the result of two embryos (one male and one female) which fused during early development. The stallion is a fully functioning male. His repro organs appear to be formed from his male DNA type, as all of his foals test to be sired by his male cell line. They also believe that his distinct brindling could be the result of one dun line and one non-dun line of cells expressing in his coat. (aside: I so wish there was a test for dun, and if there was, that the two different hair types tested positive for dun on one and negative on the other).

The researchers then performed similar testing on Sharp One. Her hair samples had come back with one DNA type, so the researchers then tested her blood. (This is fascinating.) Her blood results came back that she had two distinct DNA types in her blood. Both of her cell lines were female. They tested her 2004 foal and her previous 2003 foal, and found each descended from a separate female line. Sharp one is chimeric in her repro organs (two mares in one!) and produces two separate cell types in her eggs. Sharp One also comes from a dun background, and her brindling could also be the result of one dun and one non dun gene. (Sort of like how a calico cat has one red based X and one black based X).

So the very strong brindling could actually be the result of chimeric horses, which is a bit of a bummer because it will not reproduce itself if this is true. The less distinct brindling is thought to be heritable though.

Here is Dunbars Gold: http://www.dunbarsgold.com/

Here is Sharp One: http://members.aol.com/brindlehos/denise.htm

and yes, it *does* take chimeras and weird colours to make Quarter Horses interesting

 

[ramonmercado]

Scientists Discover Children’s Cells Living in Mothers’ Brains
The connection between mother and child is ever deeper than thought
http://www.scientificamerican.com/artic ... ain&page=2
By Robert Martone

The link between a mother and child is profound, and new research suggests a physical connection even deeper than anyone thought. The profound psychological and physical bonds shared by the mother and her child begin during gestation when the mother is everything for the developing fetus, supplying warmth and sustenance, while her heartbeat provides a soothing constant rhythm.

The physical connection between mother and fetus is provided by the placenta, an organ, built of cells from both the mother and fetus, which serves as a conduit for the exchange of nutrients, gasses, and wastes. Cells may migrate through the placenta between the mother and the fetus, taking up residence in many organs of the body including the lung, thyroid muscle, liver, heart, kidney and skin. These may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders.

It is remarkable that it is so common for cells from one individual to integrate into the tissues of another distinct person. We are accustomed to thinking of ourselves as singular autonomous individuals, and these foreign cells seem to belie that notion, and suggest that most people carry remnants of other individuals. As remarkable as this may be, stunning results from a new study show that cells from other individuals are also found in the brain. In this study, male cells were found in the brains of women and had been living there, in some cases, for several decades. What impact they may have had is now only a guess, but this study revealed that these cells were less common in the brains of women who had Alzheimer’s disease, suggesting they may be related to the health of the brain.

We all consider our bodies to be our own unique being, so the notion that we may harbor cells from other people in our bodies seems strange. Even stranger is the thought that, although we certainly consider our actions and decisions as originating in the activity of our own individual brains, cells from other individuals are living and functioning in that complex structure. However, the mixing of cells from genetically distinct individuals is not at all uncommon. This condition is called chimerism after the fire-breathing Chimera from Greek mythology, a creature that was part serpent part lion and part goat. Naturally occurring chimeras are far less ominous though, and include such creatures as the slime mold and corals.

Microchimerism is the persistent presence of a few genetically distinct cells in an organism. This was first noticed in humans many years ago when cells containing the male “Y” chromosome were found circulating in the blood of women after pregnancy. Since these cells are genetically male, they could not have been the women’s own, but most likely came from their babies during gestation.

In this new study, scientists observed that microchimeric cells are not only found circulating in the blood, they are also embedded in the brain. They examined the brains of deceased women for the presence of cells containing the male “Y” chromosome. They found such cells in more than 60 percent of the brains and in multiple brain regions. Since Alzheimer’s disease is more common in women who have had multiple pregnancies, they suspected that the number of fetal cells would be greater in women with AD compared to those who had no evidence for neurological disease. The results were precisely the opposite: there were fewer fetal-derived cells in women with Alzheimer’s. The reasons are unclear.

Microchimerism most commonly results from the exchange of cells across the placenta during pregnancy, however there is also evidence that cells may be transferred from mother to infant through nursing. In addition to exchange between mother and fetus, there may be exchange of cells between twins in utero, and there is also the possibility that cells from an older sibling residing in the mother may find their way back across the placenta to a younger sibling during the latter’s gestation. Women may have microchimeric cells both from their mother as well as from their own pregnancies, and there is even evidence for competition between cells from grandmother and infant within the mother.

What it is that fetal microchimeric cells do in the mother’s body is unclear, although there are some intriguing possibilities. For example, fetal microchimeric cells are similar to stem cells in that they are able to become a variety of different tissues and may aid in tissue repair. One research group investigating this possibility followed the activity of fetal microchimeric cells in a mother rat after the maternal heart was injured: they discovered that the fetal cells migrated to the maternal heart and differentiated into heart cells helping to repair the damage. In animal studies, microchimeric cells were found in maternal brains where they became nerve cells, suggesting they might be functionally integrated in the brain. It is possible that the same may true of such cells in the human brain.

These microchimeric cells may also influence the immune system. A fetal microchimeric cell from a pregnancy is recognized by the mother’s immune system partly as belonging to the mother, since the fetus is genetically half identical to the mother, but partly foreign, due to the father’s genetic contribution. This may “prime” the immune system to be alert for cells that are similar to the self, but with some genetic differences. Cancer cells which arise due to genetic mutations are just such cells, and there are studies which suggest that microchimeric cells may stimulate the immune system to stem the growth of tumors. Many more microchimeric cells are found in the blood of healthy women compared to those with breast cancer, for example, suggesting that microchimeric cells can somehow prevent tumor formation. In other circumstances, the immune system turns against the self, causing significant damage. Microchimerism is more common in patients suffering from Multiple Sclerosis than in their healthy siblings, suggesting chimeric cells may have a detrimental role in this disease, perhaps by setting off an autoimmune attack.

This is a burgeoning new field of inquiry with tremendous potential for novel findings as well as for practical applications. But it is also a reminder of our interconnectedness.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.


ABOUT THE AUTHOR(S)
Robert Martone is the Neuroscience therapeutic area lead for The Covance Biomarker Center of Excellence located in Greenfield, Indiana. He is a research scientist with extensive experience in drug discovery for neurodegenerative diseases.

 

[Zilch5]

That's just fascinating!

 

[Ascalon]

+1, that is mind blowing! Good find.

A

 

[Cochise]

Yes, really fascinating.

There has always been the idea that birth of a child changes the mother in some fundamental way (quite apart from it being a very traumatic process in many cases!) - maybe this is the first hint of the mechanism involved.

 

[EnolaGaia]

These findings might have been treated as incidental and unsurprising, given that some measure of cell transfer via the placental connection has long been acknowledged.

The result that makes this remarkable is the claim that fetal cells weren't just incidental debris in mommy's body, but were actually embedded in mommy's operational structure(s) (e.g., the brain).

 

[Monstrosa]

There was an article on microchimerism in NS a couple of years ago. It mentioned the case of a woman who discovered she wasn't the mother of her own daughter.She was however her grandmother.

 

[Cochise]

There was an article on microchimerism in NS a couple of years ago. It mentioned the case of a woman who discovered she wasn't the mother of her own daughter.She was however her grandmother.

Que? Can you explain that a bit further, I seem to have suddenly become hard of thinking!

 

[Monstrosa]

She had had a female pregnancy which resulted in her being invaded by cells from her daughter. These formed ovarian tissue which produced an egg which was fertilised by her male partner. This resulted in her bearing a child (I believe it was a daughter though I may be incorrect), this child was later tested for a paternity case and was discovered not to be the woman's daughter.

Simples.