She's Her Own Twin | Hacker News Reader

She's Her Own Twin

abcnews.go.com

121 points001sky95 comments

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?

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.

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.

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.

I think the parent's point is that, while rare in practice, well-qualified physicians should easily identify the unusual situation and propose the alternate hypothesis.

As an aside, this fact was of great annoyance to me when I was younger, as the child of two pathologists trying to watch the tv show House. If you're not familiar, it's a medical mystery show with a genius misanthrope doctor named House who diagnoses people with extremely rare diseases, almost killing them in the process.

It was a regular occurrence for one of my parents to walk through the room while I was watching the show, in the first 5 minutes, and throw out, "they obviously have x (vasculitis, chimerism, etc.)," thus ruining the rest of the episode for me. Of course, they never actually watched the show, since from their perspective it was just an incompetent medical team torturing some patient.

A site with a medical review by a doctor of every "House" episode: http://www.politedissent.com/house_pd.html

That your parents and the parent commenter react in this way ("it's obvious") is by design of the author of the piece and the author of House.

I can watch an episode of House and anticipate "they obviously have lupus", which makes me feel intelligent and satisfied even though I can see they are planting obvious clues from the very start which a diagnostician would be mind-numbingly stupid to ignore.

The same with the headline of this article. It's designed that way. In reality, you don't get to read the headline or watch the episode before making a clinical decision.

Regarding House: in mid-series episodes, I believe they occasionally subvert this by planting clues for the wrong thing. At least, I enjoyed being wrong in those episodes.

>The state was still so suspicious of Fairchild that when she gave birth to another child, a court officer stood in the delivery room to witness an immediate DNA test.

If you go as far as that, why wouldn't you test mitochondrial DNA? Using Ocamm's razor myself, I will speculate that she wasn't able to get a very good lawyer.

I see no reason why a mitochondrial DNA test would be helpful - your point is that the mitochondria are maternally inherited?

1. Mitochondrial DNA is less apt than regular DNA to accurately identify motherhood since it has a low mutation rate.

2. The mitochondria would still come from the chimeric cells which still are a generation away from the mother's cells.

3. If you have have considered the possibility of chimerism, there are much simpler tests - e.g. the tests that they did do.

AFAIK -and please do correct me if I am wrong - twins have the same mitochondrial DNA, therefore even if she is a chimera all her cells should share the same mitochondrial DNA.

And isn't testing for mitochondrial DNA fairly simple/cheap?

Mitochondrial DNA between twins is expected to be almost identical, but you and I also have extremely similar mitochondria: since it doesn't recombine and rarely mutates. So, you have to get to a much deeper level to identify the differences.

Even if it's now possible/cheap, that's a recent development.

mtDNA is good for finding your (maternal) ancestral group, less so for your immediate relatives.

there is no Occam's razor when you're doing an in depth investigation. Either they do a cursory DNA test or they try testing the father too, and then everything is in depth.

(well I come form a country where the judicial system is inquisitory, not accusatory, so maybe I'm biased in my point of view)

We don't really know how common chimerism, because it is expensive to test for. It requires sampling many different tissues/ parts of the body and comparing the gentic material found in each. Some kinds of chimerism are easy to detect and are believed to be relatively common. See: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.149...

What if a woman tests specifically as being the aunt instead of the mother, but also all her sisters (if any) test as aunts? Do we assume that the woman had a sister that none of her other sisters knew about, who she hid in the basement her whole life, impregnated with the woman's husband's sperm, raised the child as her own, repeated this several times, and then finally murdered the sister and hid her body?

"Chimerism is a possible explanation but vanishingly unlikely. Two identified cases, ever (i.e. none before this)."

http://en.wikipedia.org/wiki/Chimera_(genetics)#Humans gives an earlier case and references http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.149..., which states blood type chimerism occurs in 8% of twins, 21% of triplets.

So, chimerism in the broad sense isn't that rare. I have no idea whether that is different from what is described here, but I would think it isn't. Those blood cells have to come from somewhere.

Chimerism also occurs as a result of organ transplants.

"It's a rare condition called chimerism, with only 30 documented cases worldwide."

It's very rare but not THAT rare.

I would disagree: it's certainly uneducated to use Occam's Razor as an excuse to be lazy, or perhaps to ruin another person's life based on one piece of evidence. The children's father vouched for her, she has witnesses to the birth of these children, etc. In fact, everything lines up with the children being hers except the DNA test results.

I would argue Occam's Razor decides against such a large conspiracy and, instead, points to problems with the test.

When did you first learn of human chimerism? This story is from 2006, about a dispute in 2002. Social workers aren't the most scientifically-literate, and bureaucracies are often under the spell of folklore-beliefs in the certainty of genetic science, picked up from TV or state prosecutors. (Even medical 'professionals' aren't always up-to-date on topics that were considered only vanishingly-rare curiosities, when they were in med school decades ago.)

Awareness of chimerism has risen a lot in the last decade, and if you learned about it yourself in the last 10 years, it might have been due to followup coverage from this and similar cases.

And while this 2006 article describes it as a 'rare' condition ("only 30 documented cases worldwide"), in fact the more scientists look the more they find it. There's since been evidence that on a small scale, cells pass from mother-to-child and child-to-mother in the womb, and these cells are still present in blood or brain decades later... meaning almost everyone might be a chimera.

http://www.nytimes.com/2013/09/17/science/dna-double-take.ht...

There was a CSI episode from 2004 that had a human chimera as the villain.

The USA has 319 million people, that means every federal agency is going to have to deal with hundreds of "one in a million" cases, so handling something "rare" badly is still worthy of criticism. Chimerism in humans was reported on in medical journals, and as an issue for tests, since at least the 1950s and appears in the titles of all sorts of academic papers from the fields of biology and medicine from there to now.

I would have thought that if the father is saying she's the mother, she's saying she's the mother, she has the birth certificates saying that she's the mother, witnesses to the births like her parents and there is no person missing those children or claiming to be the real mother it would be reasonable to consider the possibility it is an edge case even if you still thought fraud was more likely.

Wasn't a federal agency; instead a subdivision that has 2% of the US population. So, it's possible in a hundred years, most such bureaucracies won't see a single such case.

Caseworkers don't Google extreme scenarios regarding obscure words ("chimerism") that they've probably never heard of before. Apparently, neither the mother nor her own obstetrician nor her lawyer came up with this theory, either, for quite a while, so who's fault is that? (The people with the most at stake couldn't find the magic research promptly, either.)

It wasn't until after the 2002 paper about the Keegan case, and then other media coverage of this Fairchild case, and then followup stories/dramas and more recent research, that people outside of research had any idea anything like this could happen. No, low-level state caseworkers are not going to come up with the idea themselves. And the fact they kept running tests, including monitoring a live-birth-and-immediate-DNA-test, and deferring final judgement, indicates that the system was entertaining the possibility that this was an edge case.

There's some serious hindsight bias in the know-it-all criticisms here.

I first learned about chimerism in the early 2000s, but it was a huge shock to me (it has some very deep implications beyond the scope of this article), and I was a biologist at the time.

Long ago I was pretty skeptical of the absurdly high confidence levels in forensic DNA testing because they made a number of very basic assumptions, which chimerism (among other things) show to be wrong, at a rate within the population which is higher than the reported confidence rate.

Familial link a different type of test than what the Social Services people order. They probably didn't think to do so.

Egg extraction is a very intrusive and painful procedure.

The social services people deal with thousands of people, and develop fairly rigid procedures designed to address more common issues, like people committing fraud. They are also legitimately concerned for the child's welfare, because they can be held accountable when things go wrong.

Testimony of the doctor and father aren't necessarily reliable. Who's to say the baby delivered was the baby birthed by the doctor? Who's to say that the father did't have two pregnant partners (happens often)?

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.

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.

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.

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.

> One probability mentioned is that she is acting as a surrogate mother

No, this doesn't make any sense. A surrogate mother doesn't RAISE the children she gives birth to. That would just make her a regular mother. Why would they take away her children when no one has come forward to claim them? There's no crime. It's not illegal for your DNA to not match your childrens' DNA.

> Why would they take away her children when no one has come forward to claim them?

Because you have no idea where the genetic mother could have come from, anywhere in the world (and given vitrification, anywhen), the absence of evidence doesn't show much. What do you do, put up an ad in the classifieds: 'are you missing two embryos? please cal 911'?

As the other commenter says, this is an interesting failure mode which it's not clear you can do much about without allowing many other severe failures: it's much more likely that it's an extreme fraud which has beat detection thus far than chimerism, which makes the actual chimeras go through a lot to prove the latter, but if you loosen the standards, then what...?

It still doesn't make any sense. You have a women who has provably given birth to children that don't share her DNA, and who is bringing them up as her children.

Taking them away solves nothing. In fact, it's inhuman to the point of insanity. It's also financially nonsensical, since the cost of children in care is dramatically higher than social assistance, and quite likely to get worse (because of the impact on the kids of being torn from their mother).

A system not operated by idiots would have suggested a quick and cheap compromise, such as making the kids legally hers by adoption.

> You have a women who has provably given birth to children that don't share her DNA, and who is bringing them up as her children.

Yes, so? Stealing someone's kids is OK if you then bring them up while, of course, on welfare?

There was never any evidence that she stole the kids, or that they had ever belonged to anybody else. In fact, there was a vast amount of reliable, historical evidence that they were her kids.

The _only_ evidence to the contrary turned out to be wrong, and it was proven wrong when she was observed giving birth.

Otherwise, even if she had stolen the kids, the government action was insane. As I already pointed out, it costs social services a lot more to break up a functioning family than it costs to provide enough support to keep it together.

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.

I wonder how many other chimeric women have had their children taken away without knowing how to fight it?

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.

Or perhaps more pragmatically, to simply deny her claims for assistance until she can prove her maternity.

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.

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.

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

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).

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.)

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.

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.

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?

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.

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.

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..."

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

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.

honestly, in her situation, I would probably have run away with my family at some point, out of fear of losing them.

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.

Right, they were not wrong to investigate further. They were wrong to take such extreme action, pending the results of further investigation.

Attempts to defraud the government are punished by losing one's children? Can you point to a particular law that establishes this? I'll certainly think twice before grabbing extra maps at highway rest stops from now on...

In the absence of any complaint from any interested party, the default action should not be "break up this family and parcel out the kids to foster homes where they're more likely to be abused and will definitely cost the government more." We should have less empathy for powerful and stupid bureaucrats and more empathy for their victims. This is especially so now that they have total surveillance powers over us, so our every private expression can be misconstrued by cretins to justify any action they'd like to take.

In this case, the fraud is that they aren't her children (that was the accusation, not the reality). They'd be removed because she had either borrowed them from someone to conduct the fraud or "borrowed" them (read: potential for kidnapping) them from someone and committed a crime in addition to attempting fraud.

Was this not clear in the article? They didn't believe the children were hers. That was the entire premise of the government's involvement after the initial exams.

They weren't taking the children to give them to someone deemed more likely to be a parent, or indeed to someone who even claimed to be a parent. They were just taking them. If you think this makes any sense at all, you've got the burden of proof reversed. Yay totalitarianism!

They did not (unless I missed it again after a third read of the article) take the children away. They threatened to because they were not (per the DNA) her children. That's the crux of the issue. They appeared to be someone else's children, she had no paperwork for adoptions. She denied that in vitro was used for conception. She had, if these results were correct and she were not a chimera, no apparent legal claim to these children. That meant they came from somewhere else, which is what the state would've been left trying to determine if the chimerism hadn't been discovered.

If someone comes to you with a story that completely contradicts all evidence ("I didn't do it, I just look exactly like the guy that did and happen to have the same name and live in the same house.") you wouldn't believe them. The story contradicted the physical evidence. Her pregnancy and delivery only confused it because it indicated that, rather than the children being abducted, in vitro was probably being used (again, there was no reason to suspect chimerism given its rarity and extreme obscurity at the time). Labs repeatedly showed that the children were not hers. In 999,999 cases out of a million they would have been correct, that she was conducting some sort of fraud.

This isn't totalitarianism. That'd be, they found the DNA didn't match and took the kids from her and the father that instant, locked her up and even after the discovery of chimerism kept her imprisoned for fraud and refused to allow visitation with her children. This was an unfortunate case that ended well (though stressful throughout).

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.

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

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

Well, they knew who the fathers were; it was a question of "who's the mama?"

In that case sure, but a father can also be a chimera.

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.

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?pagewan...

It's been muddied over the years, Tyler has since said he never claimed to be chimeric.

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.

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".

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?

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.

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/Ger...

FYI this article is from August 2006

Faster read:

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

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!).

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

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.")

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?

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.

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.

I cannot fathom why you are telling me this. I am abundantly familiar with these facts.

Tetragametic chimerism

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

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

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.

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

'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.

"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.)

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.

Well, I don't agree. If it was twins and they "fused" and you are going to assume one "murdered" the other, then which one is the murderer? It is a serious question. Also, how did the one baby "murder" the other? What does a baby in utero have on hand to attack its twin? The body kills invaders by, essentially, eating them (white blood cells engulf and consume microbes). At the cellular level, it is a battle and it is a case of eat or be eaten.

I realize humor is a big risk on hn. But, for me, it seems to be a big risk anywhere. (shrug)

IANAB, but the way things went down was probably more like this: Two embryos, composed entirely of stem cells, were growing adjacent to each other and bumped into each other, forming a larger embryo composed entirely of stem cells. The stem cells probably aren't really aware that their neighbors have slightly different DNA, so they just cooperate like stem cells do in forming a single human being.

Yeah, I actually get that. I am not the one who called it murder. I was kind of mocking the idea that it was murder.

Thx.

No, it's not "a person murdering other person." Definitely and absolutely not "a woman murdering the twin." The small set of cells is still not a person. The cells just started to grow (multiply) together instead of separately.

If you believe that the "person" starts as soon as the chromosomes of the two parents mix, you probably have some strong religious views, but then try to inform yourself how much such "persons" become destructed all the time and question who made the world to be so:

http://www.pregnancyloss.info/info-howcommon.htm

During the first week: "It is estimated that 3 out of 4 eggs that are fertilized (..) either do not attempt to implant or fail at implantation."

Do you call those "murders" too? If you do, by whom? If not, why do you call that other cell behavior, where the two sets continue to grow together (note: both sets continue to live!) a murder?

Well it seems to me that it would be an considered accidental death. Of course, if 75% of egg fertilizations result in the death of a person, then having unprotected sex shows a callous disregard for human life.

Still in the article case, there's certainly no "death" of the genetic information of both "twins." They both still live inside of the same body: one in some organs, another in the rest of the organs of the same body. If the "person" exist as soon as the egg and sperm mix, both of the mixes exist and live in the same body, that is, both "persons" according to that (in my opinion, just constructed out of the suspicious religious premises) definition are alive.

And under different definition of the person (which I prefer, as something that has to have "a personality" to be considered as a person) there was always only one person: the woman that has different DNA in different organs of her. The joining of the different cells happened before a functional organism existed, and since then, it's only one.

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

Using a test for interface rather than implementation maybe?

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

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.

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.

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.

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

Reply on news.ycombinator.com