8 ms·

She's Her Own Twin

121 points by 001sky 12y ago

chadrs 12y ago
Think about the implications for all the "who's the daddy" day-time television shows!
- delinka 12y ago
  Well, they knew who the fathers were; it was a question of "who's the mama?"
  - ars 12y ago
    In that case sure, but a father can also be a chimera.
    - saalweachter 12y ago
      Yeah, but with the father the semen would hopefully not be more than the third or fourth thing tested, if you kept testing. Ovums are much harder to get to.
deleted 12y ago
[deleted]
derekp7 12y ago
This is one of those cases where, even though the science is correct (the children didn't contain the same DNA as the mother's blood), the interpretation was way off (that these children weren't hers), and almost ended in a travesty of justice. Have we really come that far from the days of the Salem witch trials, and the tests they used to determine if someone was guilty of witchcraft?
- cheez 12y ago
  The main hold the state has over the people now is taking away their children or livelihoods. It used to be death so it's kind of an improvement. Once the full effect of interference comes to light, the pendulum will swing back closer to something sensible, though one must feel for the people caught up in it in the meantime.
- amirmc 12y ago
  When you fully believe that a test that is "100 percent foolproof" and impartial, it's easy to convince yourself that the person in front of you must be lying. In this case the implicit assumption was something like the following: A perfect DNA match implies parentage, therefore, parentage implies a perfect DNA match. As this article shows, the latter isn't always true. I'm sure the former isn't true either, but I'm trying to describe how most people think about these things.
  - DougN7 12y ago
    That's the thing that is worrisome - ever assuming our knowledge is 100% solid. When we're in a reflective mood, we say we'd never do that. But it happens all the time. I remember in sixth grade learning that stellar red shift absolutley proved the universe was not expanding, thus provin the big bang. Well, despite KNOWING, turns out it was wrong - the universe was expanding after all. In this case it didn't change the underlying meaning, but was wrong. That left me questioning science more than I should. I can say I hate hearing "now we know..."
bazzargh 12y ago
This famously came up in cyclist Tyler Hamilton's 2005 suspension for doping, casting doubt upon the identification of his blood: http://www.nytimes.com/2005/05/10/health/10bloo.html?pagewanted=all&_r=0 http://www.nytimes.com/2005/05/10/health/10bloo.html?pagewan... It's been muddied over the years, Tyler has since said he never claimed to be chimeric.
ninguem2 12y ago
But if she is a chimera and "her own twin" then she is her kids' genetic aunt and that should show up in DNA testing. 23andme kept telling me that so and so was my 3rd cousin until I blocked that "feature".
voidlogic 12y ago
As soon as a read the first sentence + headline, I thought, wow, I bet she is a chimera! If you were the birthing doctor and you got her call, how could this thought not cross your mind? As for the people doing the genetic test, weren't they a little surprised that even if she wasn't the kids Mom, she was their aunt? Why didn't they think to suggest the authorities look at the mitochondrial DNA. Without a mitochondrial DNA mismatch the states aggressiveness is completely unfounded. I'm so confused by the ineptitude of the medical and genetic professionals in this case. I'm also confused by the state, if the birthing doctor and father were to vouch, shouldn't that imply a less aggressive and more thoughtful investigation is in order? Couldn't they extract an egg from each ovary and do a DNA test?
- ronaldx 12y ago
  It's not uneducated to use Occam's razor: if someone tests as not being the mother, they almost always are not the mother. This is an every day occurrence. Chimerism is a possible explanation but vanishingly unlikely. Two identified cases, ever (i.e. none before this). This is news because it's exceptional.
  - voidlogic 12y ago
    I'm not disagreeing with you in thinking the scam is more likely at first glance, but as soon as there was compelling evidence it was not a scam, the professionals involved should have shared their awareness of the obvious biological possibly. The smoking gun in this case that there was not a scam, but something more going on is the fact that she was her kids aunt.
    - ronaldx 12y ago
      Apologies for editing my point above. Chimerism is well-studied because it's biologically interesting, but most social/medical professionals are not expected to come across human chimerism in their whole career. Chimerism not often documented in humans and the other possibilities (e.g. surrogacy scam) are hugely more probable explanations.
nickfargo 12y ago
Faster read: http://en.wikipedia.org/wiki/Chimera_(genetics)#Humans http://en.wikipedia.org/wiki/Chimera_(genetics)#Humans
GigabyteCoin 12y ago
FYI this article is from August 2006
ronaldx 12y ago
This article doesn't totally add up. If the mother was chimeric, she would be chimeric with a 'twin' from the same (grand)mother and father. Therefore her 'twin' chimera would share 50% of her DNA, as any regular sibling. This would be identifiable on a DNA test as a close relative: she would be genetically equivalent to an aunt rather than a mother. It's also surprising that they had to test the thyroid when the gametic cell line is the important one (wikipedia suggests they tested her cervix).
- gojomo 12y ago
  If the tests were reported to that level – and we're talking 2002 here – the fact that the child appeared to be from another relative wouldn't necessarily put the caseworkers at ease. (Was the child handed off between siblings as a form of welfare fraud?) They got lucky with the thyroid test in the Boston (Keegan) case. The chimeric cells can be anywhere, in any proportions. (There's no guarantee the complete thyroid, or complete ovary is a single genome... so the 'luck of the stick' could change the results.)
- Jtsummers 12y ago
  Siblings don't share a guaranteed 50% of DNA, there's actually a chance (though remote) that they'd share no DNA. Assuming each chromosome of a pair has an equal chance of being passed on (someone else got info on what, if anything, is known to change these odds?). So there are 2 x 2^23 possible chromosome sets. While the odds are low, it's entirely possible that two siblings with the same parents would have less than 50% of their DNA in common. In the case of a chimeric individual, if they already were below 50% DNA in common, then the children they produce might appear as only distantly related, nieces and nephews at best.
  - ronaldx 12y ago
    True in theory, but unlikely to the point of irrelevant. Assuming chromosomes are inhereted whole, the probability that siblings share less than 25% DNA - the equivalent of one further generation away - is 0.00531 (0.5% chance). But chromosomes are not inherited whole - they recombine. This hugely reduces the probability even from that start point.
ZoFreX 12y ago
Single page link: http://abcnews.go.com/Primetime/shes-twin/story?id=2315693&singlePage=true http://abcnews.go.com/Primetime/shes-twin/story?id=2315693&s...
jevinskie 12y ago
Do all of her ovum contain the same DNA or will some ovum have DNA A while others have DNA B? Would testing the DNA of her ovum (instead of blood, hair follicle, etc.) definitively shown a genetic relationship to her children?
- ronaldx 12y ago
  The ova all come from the germline so IMHO it's overwhelmingly likely they would have the same DNA but it's not exactly guaranteed: it depends if her ovaries are chimeric.
  - gus_massa 12y ago
    It’s more complicated. The germline cells are “chosen” in a very early stage of the embryo, and later they migrate to the ovary/testes. So perhaps the tissue of the ovaries are from one chimera-twin and the germline cells and the eggs from the other one. (Perhaps each embryo selected the germline cells, and both group moved to the ovary later??) More info (I coud’t find a source with better formatting): http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GermlineVsSoma.html http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/Ger...
korethr 12y ago
While I realize that one is going to find droids in government departments like social services, the mindless robotism displayed by government agents in this case were rather disturbing. To be absolutely certain that the child is hers, they had an officer there in the room to witness the birth. And yet despite actually witnessing the birth, it was decreed that the child must not be hers because of the DNA mismatch. I can think of a scenario besides chimerism where this could happen: in vitro fertilization using eggs donated from another woman. But if someone has the means to have access to IVF, it strikes me as implausible that she'd try to scam welfare. Such implausibility should have occurred to the government agents on the case as well.
- javajosh 12y ago
  Consider this another data-point in the case against means-testing for welfare and for basic income. I fail to understand how the parentage of the children was at issue at all: the children were her dependents, she (and they) needed help. Why was parentage an issue? Did the children magically not need help if she wasn't their biological parent? We can shake our heads at how the machine we all fund chews people up and spits them out, and try to improve that machine, the better solution is to eliminate an entire class of "chewing" through simply eliminating means-testing and having something like a basic income.
  - hnal943 12y ago
    As has been pointed out, it would be easy to grab someone else's children in order to fraudulently sign up for government checks. In my own city, there was a massive fraud operation of mothers claiming to run (federally subsidized) day-care facilities and listing each other's kids as the attendees. It was all on paper of course; no kids were being looked after. That's the type of abuse that will always occur and needs to be curbed in some way.
- kghose 12y ago
  One probability mentioned is that she is acting as a surrogate mother - getting money for bearing an embryo. Also, I can see the postion of the govt. officials. You have some training in a technique, but you are not an expert. By all accounts the technique is infailable. Here is a person whose account differs from the data. Your a priori on this being clever fraud rather than a little known, one in several billion case is high. I think the officials were doing their job. It was a complex case and it went up to a complex level (courts, judges, expert witnesses). What I didn't like is the threat (We can take them away). I think we should have techniques to out fraud without threatening people who have not proven to be guilty.
Shivetya 12y ago
so by the same token no DNA evidence gathered at a crime scene would match her? But I did think it interest if not distressing to that the authorities could witness a birth and totally discard her as being the mom because of a test. Hopefully it drops the hint about all sciences, just when we think we know something there is always something else
- Lexarius 12y ago
  Depends. The article didn't reveal which parts of her had which DNA, we just know that her eggs had different DNA than whatever they were sampling from. If she left blood behind and they did a blood test, it would come out as a match. If she left some other random bit of cellular structure behind, it might not match against her blood.
001sky 12y ago
Tetragametic chimerism https://en.wikipedia.org/wiki/Chimera_%28genetics%29#Tetragametic_chimerism https://en.wikipedia.org/wiki/Chimera_%28genetics%29#Tetraga...
chris_mahan 12y ago
"People over Process" shouldn't be only for Agile software development.
Yuioup 12y ago
Is HN upvoting articles now because it has a go.com domain? This Go craziness is getting out of hand.
norswap 12y ago
The level of meddling by the government is absolutely incredible. No-one complained, they had a bunch of witness to the contrary, but still they had to go through with their procedure. Frightening times we live in, when our lives may hang on the whim of some bureaucrats.
- fragsworth 12y ago
  I wonder how many other chimeric women have had their children taken away without knowing how to fight it?
- yitchelle 12y ago
  When I read the story, I was getting frustrated at the government "knee jerk" reaction that she was immediately in the wrong. Would it not be better if the government spend the effort in determining why their DNA does not match? It seems that not enough humanity is withe social services and the courts.
  - hnal943 12y ago
    Or perhaps more pragmatically, to simply deny her claims for assistance until she can prove her maternity.
benihana 12y ago
This reminds me of Doc Daneeka from Catch-22: For those who haven't read it, he's a flight surgeon who hates flying, but since he's attached to a bomber squadron, he's required to get a certain amount of flight time a month to get flight pay. He hates flying, so he bribes the guy in charge of the flight log to just say he got his flight time. The problem, is the plane he was officially on (but not on in reality) crashed killing everyone onboard. This is the official record for the government, and since the official record says he's dead, he must have died. This causes all sorts of problems when people in the bureaucracy notice that he's not dead. Instead of accepting that their records don't match reality so the records are wrong, they reason that reality doesn't match their records so reality must be wrong. His wife realizes that it's financial beneficial for her if she acknowledges his death, so she pretends he's dead as well. It's a brilliant satire on government bureaucracy and how members of the bureaucracy take it as being fact, and until I read this story about the woman murdering her twin in the womb, it was hilarious to me. Now it's a bit more frightening. http://en.wikipedia.org/wiki/Doc_Daneeka http://en.wikipedia.org/wiki/Doc_Daneeka
- anigbrowl 12y ago
  'woman murdering her twin in the womb'?! What a bizarre and offensive thing to say. What the article says: In human biology, a chimera is an organism with at least two genetically distinct types of cells -- or, in other words, someone meant to be a twin. But while in the mother's womb, two fertilized eggs fuse, becoming one fetus that carries two distinct genetic codes -- two separate strands of DNA.
  - Mz 12y ago
    "The point is, you are alive when they start to eat you. So, y'know, try to show a little respect?" The question is: Which baby ate the other and whom do we charge with murder? (the "/s" tag does not fit here -- someone clue me as to what kind of tag I need here, k? thx.)
    - colanderman 12y ago
      I think you were downvoted because your comment, while humorous, doesn't really add to the conversation. Humor is appreciated more on HN when it is coupled with insight.
tantalor 12y ago
The article mentions surrogacy (in the context of fraud), so I wonder why the theory of her having used donated eggs was not mentioned. Would accepting donor eggs disqualify someone from receiving benefits? Also, it is a MUCH more likely explanation than chimerism.
- venomsnake 12y ago
  What I thought about that - doesn't that leave a lot of paper trails? Medical billing histories that could be combed etc. If government thinks she is surrogate - they must prove it. And DNA test just gives a fact and not a proof.
oska 12y ago
IMO, this piece [1] on Lydia Fairchild is better written and has much more information on chimerism and microchimerism. [1] http://www.psychologytoday.com/articles/201303/the-you-in-me http://www.psychologytoday.com/articles/201303/the-you-in-me
stefantalpalaru 12y ago
Viable chimeras are fascinating. How does the immune system tolerate two different definitions of self?
- adolph 12y ago
  Using a test for interface rather than implementation maybe?
- pygy_ 12y ago
  Self-recognition is the consequence of a selection process that occurs in the thymus at a young age, for T-Cells, and in the bone marrow for B-cells. https://en.wikipedia.org/wiki/Thymus https://en.wikipedia.org/wiki/Thymus First, T cells undergo "Positive Selection" whereby the cell comes in contact with self-MHC expressed by thymic epithelial cells; those with no interaction are destroyed. Second, the T cell undergoes "Negative Selection" by interacting with thymic dendritic cell whereby T cells with high affinity interaction are eliminated through apoptosis (to avoid autoimmunity), and those with intermediate affinity survive. See also https://en.wikipedia.org/wiki/V%28D%29J_recombination https://en.wikipedia.org/wiki/V%28D%29J_recombination V(D)J recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin (Ig) and T cell receptors (TCR) production of the immune system. V(D)J recombination takes place in the primary lymphoid tissue (the bone marrow for B cells, and Thymus for T cells). V(D)J recombination nearly randomly combines Variable, Diverse, and Joining gene segments in vertebrate lymphocytes, and because of its randomness in choosing different genes, is able to diversely encode proteins to match antigens from bacteria, viruses, parasites, dysfunctional cells such as tumor cells, and pollens.
- gizmo686 12y ago
  My guess would be that it simply lacks the ability to differentiate between them. Consider that we regularly transplant organs between individuals who are less related than twins, and who have fully grown before the transplant.
Mz 12y ago
I had seen this story before. I find this kind of thing enormously frustrating and it hits a nerve for me personally: Having figured out how to get well in the face of having an incurable and deadly genetic disorder, I basically get treated like I have Munhausen by Internet for trying to talk about it. And it just frustrates the hell out of me, on so many levels. And it seems to make no difference to talk about it. Talking about my frustration winds up being another excuse to dismiss me as a nutcase and attention whore. So I can identify with the frustration of the two women in the story. (I can't help but wonder if sexism plays a part here. I am also female. Questioning my sanity seems like a more PC thing to do than dismiss as "girls are too stupid to come up with any good ideas.")
- chromaton 12y ago
  I read some of your stuff on your various blogs and kept looking for a post where you described what illness you actually had. I never found it. Is the problem that people don't believe you had a particular disease to begin with?
  - Mz 12y ago
    No. There are a long list of problems. My official diagnosis is "atypical cystic fibrosis." Cystic fibrosis is quite deadly and when I was active on various CF lists, no one believed me that I was, in fact, getting well. That seems to be the issue in a nutshell: That no one believes it can be done, much less by a former homemaker and mom. I have a long list of credibility problems. Listing them here would not help my credibility. I intentionally lowered my profile because being more open about things was only attracting really ugly personal attacks. It was all downside, no upside. I have actually made some progress on some of the things I think need to be solved in order to move forward on, someday, helping people. But I find it maddeningly frustrating the degree to which I simply am not taken seriously most of the time, by most people.
    - kghose 12y ago
      CF is a very broad spectrum disease. People have been diagnosed in their 60s and 70s, coming in with a peripherally related complaint. Not all CF manifestation is deadly. The gold standard test is the sweat test and the real test is a full panel genetic screen.
louthy 12y ago
I wonder how common this is? I have different coloured eyes, which can be caused by Chimerism. Twins are very common in my family and I have two brothers who are identical twins, so I have often wondered whether Chimerism is the cause of my condition (although not enough to do anything about it!).
- deleted 12y ago
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m_mueller 12y ago
Here's a fascinating Radiolab episode dealing with this subject: http://www.radiolab.org/story/91597-mix-and-match/ http://www.radiolab.org/story/91597-mix-and-match/.
skrebbel 12y ago
Why would government agencies take away kids from a mother only because they don't believe they're hers? If the whole family wants to stay together - the kids, the mom, the dad (assuming the dad is in the picture), then why does it matter how things got to be? It's a family by all definitions that matter.
jessaustin 12y ago
Bureaucrat A: We've found something slightly odd about this family. Bureaucrat B: Thank you for bringing this to our attention. We will now completely fuck up their lives.
- malka 12y ago
  honestly, in her situation, I would probably have run away with my family at some point, out of fear of losing them.
- Jtsummers 12y ago
  It's not just her family. She was applying for government assistance. People try to defraud government programs so countermeasures are developed. One is ensuring that the children people claim as dependents (and thus will get money for) are, in fact, their children. If someone turns up with 3 kids and falsified documents, DNA tests would reveal the attempted fraud (assuming the kids aren't their identical twin's or a very genetically close sibling's). In this case the bureaucrats, as you call them, were faced with someone who appeared to be attempting to defraud the government. She insisted (rightly) that they were her children, but initially the DNA evidence pointed to that being a lie. They asked about them being her sister's children (suggesting she was the aunt), she denied this. They inquired about surrogacy, in vitro, etc. She insisted that the children were conceived normally and delivered by her. Once the latter was proven, the DNA still didn't match which left the surrogacy angle (which presented a risk that she'd defrauded someone else). She'd likely get assistance if it had been surrogacy (but she kept the kids legitimately) or in vitro with donated eggs and above board, but she kept insisting (because she was right) that it wasn't, which left the investigators in a bind. The facts didn't match the claims. It's unfortunate that she happened to get caught up in all of this when she was totally innocent of any wrongdoing or attempted fraud, but given the odds of chimerism the bureaucrats were not wrong to investigate further. Now that the condition is known and understood hopefully this will be resolved more quickly for future chimeras.
  - ensignavenger 12y ago
    Right, they were not wrong to investigate further. They were wrong to take such extreme action, pending the results of further investigation.
mnw21cam 12y ago
Bit of information which is on Wikipedia, but missing from the article: A lawyer for the prosecution heard of a human chimera in New England, Karen Keegan, and suggested the possibility to the defence... Which restores a little bit of one's faith in humanity.

She's Her Own Twin

121 points by 001sky 12y ago

chadrs 12y ago

Think about the implications for all the "who's the daddy" day-time television shows!

delinka 12y ago
Well, they knew who the fathers were; it was a question of "who's the mama?"
- ars 12y ago
  In that case sure, but a father can also be a chimera.
  - saalweachter 12y ago
    Yeah, but with the father the semen would hopefully not be more than the third or fourth thing tested, if you kept testing. Ovums are much harder to get to.

deleted 12y ago

[deleted]

derekp7 12y ago

This is one of those cases where, even though the science is correct (the children didn't contain the same DNA as the mother's blood), the interpretation was way off (that these children weren't hers), and almost ended in a travesty of justice. Have we really come that far from the days of the Salem witch trials, and the tests they used to determine if someone was guilty of witchcraft?

cheez 12y ago
The main hold the state has over the people now is taking away their children or livelihoods. It used to be death so it's kind of an improvement. Once the full effect of interference comes to light, the pendulum will swing back closer to something sensible, though one must feel for the people caught up in it in the meantime.
amirmc 12y ago
When you fully believe that a test that is "100 percent foolproof" and impartial, it's easy to convince yourself that the person in front of you must be lying. In this case the implicit assumption was something like the following: A perfect DNA match implies parentage, therefore, parentage implies a perfect DNA match. As this article shows, the latter isn't always true. I'm sure the former isn't true either, but I'm trying to describe how most people think about these things.
- DougN7 12y ago
  That's the thing that is worrisome - ever assuming our knowledge is 100% solid. When we're in a reflective mood, we say we'd never do that. But it happens all the time. I remember in sixth grade learning that stellar red shift absolutley proved the universe was not expanding, thus provin the big bang. Well, despite KNOWING, turns out it was wrong - the universe was expanding after all. In this case it didn't change the underlying meaning, but was wrong. That left me questioning science more than I should. I can say I hate hearing "now we know..."

bazzargh 12y ago

This famously came up in cyclist Tyler Hamilton's 2005 suspension for doping, casting doubt upon the identification of his blood: http://www.nytimes.com/2005/05/10/health/10bloo.html?pagewanted=all&_r=0 http://www.nytimes.com/2005/05/10/health/10bloo.html?pagewan... It's been muddied over the years, Tyler has since said he never claimed to be chimeric.

ninguem2 12y ago

But if she is a chimera and "her own twin" then she is her kids' genetic aunt and that should show up in DNA testing. 23andme kept telling me that so and so was my 3rd cousin until I blocked that "feature".

voidlogic 12y ago

As soon as a read the first sentence + headline, I thought, wow, I bet she is a chimera! If you were the birthing doctor and you got her call, how could this thought not cross your mind? As for the people doing the genetic test, weren't they a little surprised that even if she wasn't the kids Mom, she was their aunt? Why didn't they think to suggest the authorities look at the mitochondrial DNA. Without a mitochondrial DNA mismatch the states aggressiveness is completely unfounded. I'm so confused by the ineptitude of the medical and genetic professionals in this case. I'm also confused by the state, if the birthing doctor and father were to vouch, shouldn't that imply a less aggressive and more thoughtful investigation is in order? Couldn't they extract an egg from each ovary and do a DNA test?

ronaldx 12y ago
It's not uneducated to use Occam's razor: if someone tests as not being the mother, they almost always are not the mother. This is an every day occurrence. Chimerism is a possible explanation but vanishingly unlikely. Two identified cases, ever (i.e. none before this). This is news because it's exceptional.
- voidlogic 12y ago
  I'm not disagreeing with you in thinking the scam is more likely at first glance, but as soon as there was compelling evidence it was not a scam, the professionals involved should have shared their awareness of the obvious biological possibly. The smoking gun in this case that there was not a scam, but something more going on is the fact that she was her kids aunt.
  - ronaldx 12y ago
    Apologies for editing my point above. Chimerism is well-studied because it's biologically interesting, but most social/medical professionals are not expected to come across human chimerism in their whole career. Chimerism not often documented in humans and the other possibilities (e.g. surrogacy scam) are hugely more probable explanations.

nickfargo 12y ago

Faster read: http://en.wikipedia.org/wiki/Chimera_(genetics)#Humans http://en.wikipedia.org/wiki/Chimera_(genetics)#Humans

GigabyteCoin 12y ago

FYI this article is from August 2006

ronaldx 12y ago

This article doesn't totally add up. If the mother was chimeric, she would be chimeric with a 'twin' from the same (grand)mother and father. Therefore her 'twin' chimera would share 50% of her DNA, as any regular sibling. This would be identifiable on a DNA test as a close relative: she would be genetically equivalent to an aunt rather than a mother. It's also surprising that they had to test the thyroid when the gametic cell line is the important one (wikipedia suggests they tested her cervix).

gojomo 12y ago
If the tests were reported to that level – and we're talking 2002 here – the fact that the child appeared to be from another relative wouldn't necessarily put the caseworkers at ease. (Was the child handed off between siblings as a form of welfare fraud?) They got lucky with the thyroid test in the Boston (Keegan) case. The chimeric cells can be anywhere, in any proportions. (There's no guarantee the complete thyroid, or complete ovary is a single genome... so the 'luck of the stick' could change the results.)
Jtsummers 12y ago
Siblings don't share a guaranteed 50% of DNA, there's actually a chance (though remote) that they'd share no DNA. Assuming each chromosome of a pair has an equal chance of being passed on (someone else got info on what, if anything, is known to change these odds?). So there are 2 x 2^23 possible chromosome sets. While the odds are low, it's entirely possible that two siblings with the same parents would have less than 50% of their DNA in common. In the case of a chimeric individual, if they already were below 50% DNA in common, then the children they produce might appear as only distantly related, nieces and nephews at best.
- ronaldx 12y ago
  True in theory, but unlikely to the point of irrelevant. Assuming chromosomes are inhereted whole, the probability that siblings share less than 25% DNA - the equivalent of one further generation away - is 0.00531 (0.5% chance). But chromosomes are not inherited whole - they recombine. This hugely reduces the probability even from that start point.

ZoFreX 12y ago

Single page link: http://abcnews.go.com/Primetime/shes-twin/story?id=2315693&singlePage=true http://abcnews.go.com/Primetime/shes-twin/story?id=2315693&s...

jevinskie 12y ago

Do all of her ovum contain the same DNA or will some ovum have DNA A while others have DNA B? Would testing the DNA of her ovum (instead of blood, hair follicle, etc.) definitively shown a genetic relationship to her children?

ronaldx 12y ago
The ova all come from the germline so IMHO it's overwhelmingly likely they would have the same DNA but it's not exactly guaranteed: it depends if her ovaries are chimeric.
- gus_massa 12y ago
  It’s more complicated. The germline cells are “chosen” in a very early stage of the embryo, and later they migrate to the ovary/testes. So perhaps the tissue of the ovaries are from one chimera-twin and the germline cells and the eggs from the other one. (Perhaps each embryo selected the germline cells, and both group moved to the ovary later??) More info (I coud’t find a source with better formatting): http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GermlineVsSoma.html http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/Ger...

korethr 12y ago

While I realize that one is going to find droids in government departments like social services, the mindless robotism displayed by government agents in this case were rather disturbing. To be absolutely certain that the child is hers, they had an officer there in the room to witness the birth. And yet despite actually witnessing the birth, it was decreed that the child must not be hers because of the DNA mismatch. I can think of a scenario besides chimerism where this could happen: in vitro fertilization using eggs donated from another woman. But if someone has the means to have access to IVF, it strikes me as implausible that she'd try to scam welfare. Such implausibility should have occurred to the government agents on the case as well.

javajosh 12y ago
Consider this another data-point in the case against means-testing for welfare and for basic income. I fail to understand how the parentage of the children was at issue at all: the children were her dependents, she (and they) needed help. Why was parentage an issue? Did the children magically not need help if she wasn't their biological parent? We can shake our heads at how the machine we all fund chews people up and spits them out, and try to improve that machine, the better solution is to eliminate an entire class of "chewing" through simply eliminating means-testing and having something like a basic income.
- hnal943 12y ago
  As has been pointed out, it would be easy to grab someone else's children in order to fraudulently sign up for government checks. In my own city, there was a massive fraud operation of mothers claiming to run (federally subsidized) day-care facilities and listing each other's kids as the attendees. It was all on paper of course; no kids were being looked after. That's the type of abuse that will always occur and needs to be curbed in some way.
kghose 12y ago
One probability mentioned is that she is acting as a surrogate mother - getting money for bearing an embryo. Also, I can see the postion of the govt. officials. You have some training in a technique, but you are not an expert. By all accounts the technique is infailable. Here is a person whose account differs from the data. Your a priori on this being clever fraud rather than a little known, one in several billion case is high. I think the officials were doing their job. It was a complex case and it went up to a complex level (courts, judges, expert witnesses). What I didn't like is the threat (We can take them away). I think we should have techniques to out fraud without threatening people who have not proven to be guilty.

Shivetya 12y ago

so by the same token no DNA evidence gathered at a crime scene would match her? But I did think it interest if not distressing to that the authorities could witness a birth and totally discard her as being the mom because of a test. Hopefully it drops the hint about all sciences, just when we think we know something there is always something else

Lexarius 12y ago
Depends. The article didn't reveal which parts of her had which DNA, we just know that her eggs had different DNA than whatever they were sampling from. If she left blood behind and they did a blood test, it would come out as a match. If she left some other random bit of cellular structure behind, it might not match against her blood.

001sky 12y ago

Tetragametic chimerism https://en.wikipedia.org/wiki/Chimera_%28genetics%29#Tetragametic_chimerism https://en.wikipedia.org/wiki/Chimera_%28genetics%29#Tetraga...

chris_mahan 12y ago

"People over Process" shouldn't be only for Agile software development.

Yuioup 12y ago

Is HN upvoting articles now because it has a go.com domain? This Go craziness is getting out of hand.

norswap 12y ago

The level of meddling by the government is absolutely incredible. No-one complained, they had a bunch of witness to the contrary, but still they had to go through with their procedure. Frightening times we live in, when our lives may hang on the whim of some bureaucrats.

fragsworth 12y ago
I wonder how many other chimeric women have had their children taken away without knowing how to fight it?
yitchelle 12y ago
When I read the story, I was getting frustrated at the government "knee jerk" reaction that she was immediately in the wrong. Would it not be better if the government spend the effort in determining why their DNA does not match? It seems that not enough humanity is withe social services and the courts.
- hnal943 12y ago
  Or perhaps more pragmatically, to simply deny her claims for assistance until she can prove her maternity.

benihana 12y ago

This reminds me of Doc Daneeka from Catch-22: For those who haven't read it, he's a flight surgeon who hates flying, but since he's attached to a bomber squadron, he's required to get a certain amount of flight time a month to get flight pay. He hates flying, so he bribes the guy in charge of the flight log to just say he got his flight time. The problem, is the plane he was officially on (but not on in reality) crashed killing everyone onboard. This is the official record for the government, and since the official record says he's dead, he must have died. This causes all sorts of problems when people in the bureaucracy notice that he's not dead. Instead of accepting that their records don't match reality so the records are wrong, they reason that reality doesn't match their records so reality must be wrong. His wife realizes that it's financial beneficial for her if she acknowledges his death, so she pretends he's dead as well. It's a brilliant satire on government bureaucracy and how members of the bureaucracy take it as being fact, and until I read this story about the woman murdering her twin in the womb, it was hilarious to me. Now it's a bit more frightening. http://en.wikipedia.org/wiki/Doc_Daneeka http://en.wikipedia.org/wiki/Doc_Daneeka

anigbrowl 12y ago
'woman murdering her twin in the womb'?! What a bizarre and offensive thing to say. What the article says: In human biology, a chimera is an organism with at least two genetically distinct types of cells -- or, in other words, someone meant to be a twin. But while in the mother's womb, two fertilized eggs fuse, becoming one fetus that carries two distinct genetic codes -- two separate strands of DNA.
- Mz 12y ago
  "The point is, you are alive when they start to eat you. So, y'know, try to show a little respect?" The question is: Which baby ate the other and whom do we charge with murder? (the "/s" tag does not fit here -- someone clue me as to what kind of tag I need here, k? thx.)
  - colanderman 12y ago
    I think you were downvoted because your comment, while humorous, doesn't really add to the conversation. Humor is appreciated more on HN when it is coupled with insight.

tantalor 12y ago

The article mentions surrogacy (in the context of fraud), so I wonder why the theory of her having used donated eggs was not mentioned. Would accepting donor eggs disqualify someone from receiving benefits? Also, it is a MUCH more likely explanation than chimerism.

venomsnake 12y ago
What I thought about that - doesn't that leave a lot of paper trails? Medical billing histories that could be combed etc. If government thinks she is surrogate - they must prove it. And DNA test just gives a fact and not a proof.

oska 12y ago

IMO, this piece [1] on Lydia Fairchild is better written and has much more information on chimerism and microchimerism. [1] http://www.psychologytoday.com/articles/201303/the-you-in-me http://www.psychologytoday.com/articles/201303/the-you-in-me

stefantalpalaru 12y ago

Viable chimeras are fascinating. How does the immune system tolerate two different definitions of self?

adolph 12y ago
Using a test for interface rather than implementation maybe?
pygy_ 12y ago
Self-recognition is the consequence of a selection process that occurs in the thymus at a young age, for T-Cells, and in the bone marrow for B-cells. https://en.wikipedia.org/wiki/Thymus https://en.wikipedia.org/wiki/Thymus First, T cells undergo "Positive Selection" whereby the cell comes in contact with self-MHC expressed by thymic epithelial cells; those with no interaction are destroyed. Second, the T cell undergoes "Negative Selection" by interacting with thymic dendritic cell whereby T cells with high affinity interaction are eliminated through apoptosis (to avoid autoimmunity), and those with intermediate affinity survive. See also https://en.wikipedia.org/wiki/V%28D%29J_recombination https://en.wikipedia.org/wiki/V%28D%29J_recombination V(D)J recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin (Ig) and T cell receptors (TCR) production of the immune system. V(D)J recombination takes place in the primary lymphoid tissue (the bone marrow for B cells, and Thymus for T cells). V(D)J recombination nearly randomly combines Variable, Diverse, and Joining gene segments in vertebrate lymphocytes, and because of its randomness in choosing different genes, is able to diversely encode proteins to match antigens from bacteria, viruses, parasites, dysfunctional cells such as tumor cells, and pollens.
gizmo686 12y ago
My guess would be that it simply lacks the ability to differentiate between them. Consider that we regularly transplant organs between individuals who are less related than twins, and who have fully grown before the transplant.

Mz 12y ago

I had seen this story before. I find this kind of thing enormously frustrating and it hits a nerve for me personally: Having figured out how to get well in the face of having an incurable and deadly genetic disorder, I basically get treated like I have Munhausen by Internet for trying to talk about it. And it just frustrates the hell out of me, on so many levels. And it seems to make no difference to talk about it. Talking about my frustration winds up being another excuse to dismiss me as a nutcase and attention whore. So I can identify with the frustration of the two women in the story. (I can't help but wonder if sexism plays a part here. I am also female. Questioning my sanity seems like a more PC thing to do than dismiss as "girls are too stupid to come up with any good ideas.")

chromaton 12y ago
I read some of your stuff on your various blogs and kept looking for a post where you described what illness you actually had. I never found it. Is the problem that people don't believe you had a particular disease to begin with?
- Mz 12y ago
  No. There are a long list of problems. My official diagnosis is "atypical cystic fibrosis." Cystic fibrosis is quite deadly and when I was active on various CF lists, no one believed me that I was, in fact, getting well. That seems to be the issue in a nutshell: That no one believes it can be done, much less by a former homemaker and mom. I have a long list of credibility problems. Listing them here would not help my credibility. I intentionally lowered my profile because being more open about things was only attracting really ugly personal attacks. It was all downside, no upside. I have actually made some progress on some of the things I think need to be solved in order to move forward on, someday, helping people. But I find it maddeningly frustrating the degree to which I simply am not taken seriously most of the time, by most people.
  - kghose 12y ago
    CF is a very broad spectrum disease. People have been diagnosed in their 60s and 70s, coming in with a peripherally related complaint. Not all CF manifestation is deadly. The gold standard test is the sweat test and the real test is a full panel genetic screen.

louthy 12y ago

I wonder how common this is? I have different coloured eyes, which can be caused by Chimerism. Twins are very common in my family and I have two brothers who are identical twins, so I have often wondered whether Chimerism is the cause of my condition (although not enough to do anything about it!).

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m_mueller 12y ago

Here's a fascinating Radiolab episode dealing with this subject: http://www.radiolab.org/story/91597-mix-and-match/ http://www.radiolab.org/story/91597-mix-and-match/.

skrebbel 12y ago

Why would government agencies take away kids from a mother only because they don't believe they're hers? If the whole family wants to stay together - the kids, the mom, the dad (assuming the dad is in the picture), then why does it matter how things got to be? It's a family by all definitions that matter.

jessaustin 12y ago

Bureaucrat A: We've found something slightly odd about this family. Bureaucrat B: Thank you for bringing this to our attention. We will now completely fuck up their lives.

malka 12y ago
honestly, in her situation, I would probably have run away with my family at some point, out of fear of losing them.
Jtsummers 12y ago
It's not just her family. She was applying for government assistance. People try to defraud government programs so countermeasures are developed. One is ensuring that the children people claim as dependents (and thus will get money for) are, in fact, their children. If someone turns up with 3 kids and falsified documents, DNA tests would reveal the attempted fraud (assuming the kids aren't their identical twin's or a very genetically close sibling's). In this case the bureaucrats, as you call them, were faced with someone who appeared to be attempting to defraud the government. She insisted (rightly) that they were her children, but initially the DNA evidence pointed to that being a lie. They asked about them being her sister's children (suggesting she was the aunt), she denied this. They inquired about surrogacy, in vitro, etc. She insisted that the children were conceived normally and delivered by her. Once the latter was proven, the DNA still didn't match which left the surrogacy angle (which presented a risk that she'd defrauded someone else). She'd likely get assistance if it had been surrogacy (but she kept the kids legitimately) or in vitro with donated eggs and above board, but she kept insisting (because she was right) that it wasn't, which left the investigators in a bind. The facts didn't match the claims. It's unfortunate that she happened to get caught up in all of this when she was totally innocent of any wrongdoing or attempted fraud, but given the odds of chimerism the bureaucrats were not wrong to investigate further. Now that the condition is known and understood hopefully this will be resolved more quickly for future chimeras.
- ensignavenger 12y ago
  Right, they were not wrong to investigate further. They were wrong to take such extreme action, pending the results of further investigation.

mnw21cam 12y ago

Bit of information which is on Wikipedia, but missing from the article: A lawyer for the prosecution heard of a human chimera in New England, Karen Keegan, and suggested the possibility to the defence... Which restores a little bit of one's faith in humanity.