Chimera Twins Story 483
skelley writes "Below is an audio link on this morning's story on NPR about Chimera twins, or people with two sets of DNA.
It turns out that every once in a while a set of fraternal twin eggs merge into one embryo. The resulting person has two sets of DNA.
The story says it is possible for a Chimera to have different sets of DNA in different body parts. This can cause complication for body identification, DNA typing for organ transplants, crime investigation, etc.
Researchers have no idea how common this is, but suppose that it is a reasonable percentage of all fraternal twin pregnancies, which would mean millions worldwide.
No text version. NPR often doesn't publish one.
"
crime investigation problems (Score:4, Funny)
Re:crime investigation problems (Score:5, Funny)
Re:crime investigation problems (Score:5, Funny)
Re:WHY TELL US YOU ARE ATHEIST??? (Score:3, Funny)
Re:WHY TELL US YOU ARE ATHEIST??? (Score:5, Funny)
Then again, maybe its because he is an atheist and wants people to be aware that there are differing viewpoints. A great many Christians in the US seem to think that everyone else in the country is also a Christian. Stating that you're an atheist is similar to driving around with a Jesus fish on your car.
And, just as an FYI, warning an atheist about hell has about as much effect as telling the average adult that if they misbehave, Santa won't bring them any presents. In other words, none.
Hmm (Score:5, Funny)
If the DNA don't fit.. well.. uhh.. ahh shit.
Re:Hmm (Score:5, Interesting)
Re:Hmm (Score:3, Interesting)
Re:Hmm (Score:4, Informative)
You wrote:
Every human has two copies of each kind of chomosome, making a total of 46, which is ONE complete set! For some traits, one of the chromosomes has a dominant gene that is expressed, in many cases. However, sometimes neither gene dominates and they are both partially expressed.Also, a man has one X chromosome and one Y chromosome, not two of each. Half of his sperm cells will have a copy of the X, and the other half a copy of the Y. And a female's DNA is finalized when the sperm meets the egg in the mother! Any egg cells produced contain merely half of the 46 chromosomes already present in the zygote at conception! Since the grandfather's Y chromosome could never be present in a mother's DNA, she will never pass a Y to her children, which is why we never see a YY-gendered person.
There goes my number-one excuse (Score:5, Funny)
Re:There goes my number-one excuse (Score:2, Informative)
Re:There goes my number-one excuse (Score:5, Funny)
"I AM my own evil twin."
How many other kids on the playground can say that?
Re:There goes my number-one excuse (Score:3, Funny)
Re:There goes my number-one excuse (Score:5, Funny)
Gonna be more common. (Score:5, Interesting)
Re:Gonna be more common. (Score:5, Insightful)
finally, a valid excuse (Score:5, Funny)
Re:finally, a valid excuse (Score:3, Funny)
Re:finally, a valid excuse (Score:5, Funny)
Re:finally, a valid excuse (Score:3, Insightful)
There are open source streaming servers (shoutcast, Quicktime streaming server) and plenty of other, commercial servers that rely on open-standards (just like real radio) so that choice of client is irrelevant and up to the user.
My other sig was
Re:finally, a valid excuse (Score:5, Informative)
Looks like (Score:2, Interesting)
Re:Looks like (Score:3)
But maybe that's not such a good idea... if you can't quite reach your beverage, you could suddenly evolve into a creature with far longer arms, but it would probably be quite incapable of drinking it.
Heehee (Score:5, Funny)
Oh ho ho, methinks they'll change their mind very shortly.
Re:Heehee (Score:5, Informative)
You're a dipshit spreading FUD.
From http://www.npr.org/about/place/corpsupport/financi als.html [npr.org]
There is no 'budget line' for NPR in the fedral budget.
Re:Heehee (Score:3, Insightful)
Agreed. It is a rough estimate, but I still think that it shows that the amount of federal money that actually makes it to NPR is low.
If NPR doesn't need any goverment money they shouldn't take any of it. It would shut up their detractors and the much-talked-about liberal private radio station would be born.
Two points: agreed... if they don't need the cash, they shouldn't take it... but I do think they need it
Re:NPR Funding (Score:3, Insightful)
You can only believe that if you listen exclusively to Rush, and he told you so.
If you actually listened to NPR, you would realize that they are the only organization besides the BBC that is anywhere near "fair and balanced."
Odd (Score:2, Interesting)
Re:Odd (Score:5, Informative)
I would imagine that the number of viable chimeric embryos is much lower than the total number of chimeric embryos; in fact, you could probably graph something like an inverse logistic curve of surviving chimeric embryos vs. days of pregnancy.
Re:Odd (Score:5, Interesting)
Now that I've got that out of the way... I'd say that quite often since differentiation of cell occures very early on, and that often the other allele in the pair is inactivated, it may be that one tissue type is derived from the one set of genes, and another type is derived from the other set of genes. That person may be a a higher risk of developing auto-immune diseases. Your proposition of spontanious abortion is quite possible... but remember Jurassic Park (life will find a way!).
Re:Odd (Score:3, Insightful)
Hee hee, a molecular biologist quoting Jurrassic Park?
Re:Odd (Score:5, Interesting)
This isn't as big a problem as you'ld think; as long as the two embryos merge before the cells start to differentate it could work.
There are some really creepy experiments with mice where they did this on purpose with white and black mice, and got striped (!) mice that always had exactly 13 stripes (well, sometimes adjacent stripes were the same color, but if you made enough mice you could tell) - this told them that the skin developed from 13 cells, etc.
Presumably if you're mixing siblings you won't get stripes...
picture (Score:5, Funny)
Closeup [plantanswers.com] before eyes are formed.
In-vitro development in the lab. [plantanswers.com]
Displaying remarkable inteligence [plantanswers.com] as they swarm and are about to devour their much-bigger and unsuspecting prey (apparently striped mice are carnivorous)
um...mod parent funny? (Score:5, Insightful)
Re:Odd (Score:3, Funny)
Well, IANAAA (I Am Not A Acronym Abuser) but what was the point of you using an obscure acronym if you had to spell it out for everybody anyways?
Re:Odd (Score:3, Informative)
Chimera twins would contain both complete sets of "sibling" DNA, which could theoretically be female and male DNA combined, let alone multiple blood types.
One might assume that multiple blood types would result in a (naturally) aborte
Re:Odd (Score:3, Interesting)
A detective talks about the possiblity of someone like this commiting murder where there is a blood sample left at the scene, but when they take a swap sample from the inside of the suspects mouth it shows a completely different dna.
Two blood types: YES! (Score:5, Interesting)
IANAL, but IUTWIBB ... I used to work in blood banks doing crossmatches. A small number of people have two different ABO blood types. They are not "AB", they have some red blood cells that are pure "A" and some that are pure "B" and that is violating Mendelian genetics. The same mechanism that creates this could easily create other "blood chimeras" with the other several hundred lesser-known blood types. And a third mechanism (sex chromosome abnormalities) can create a kind of blood chimera that has nothing to do with twins.
Apparently, most of these blood chimera individuals shared a blood supply with a non-identical twin before birth (the cells that make blood and populate your bone marrow float around the fetal blood supply while waiting for bones to develop to give them a place to settle, and the placentas and their blood vessels can merge without producing conjoined twins). In some cases, people are unaware that they had a twin because he or she died early in gestation and was spontaneously aborted (or disintegrated by the mother's defense mechanisms, or walled off in the mother or living twin). They show up in the National Enquirer when someone is operated on for a cyst and it has bits of the encysted twin in it.
As many as 8% of non-identical twins may have chimeric blood. Some people are microchimeric--they have a small amount of blood of a different type in their system that has persisted from a blood transfusion or passed across the placental barrier from their mother before birth.
"Blood chimerism" does NOT cause a problem for the person with the chimerism as far as receiving blood in a transfusion ... they will tolerate any phenotype they possess if you transfuse it - they have had it since they were fetuses and it is "self" in the immunological sense of the word.
It can, however, be hell on blood banks trying to figure out what the heck is wrong with the blood during the initial typing and screening in a transfusion where the blood chimera is the donor. The potential recipient is not at risk because the tech says &^$^$#%@!!!, sets the donor unit back in the frig with a "do not use" note and sends it off to a research lab to find out what's going on. That's how you usually find blood chimeras and new blood types ... anomalous results in what should be a routine crossmatch.
Women already do this. (Score:4, Funny)
Re:Women already do this. (Score:5, Interesting)
Again, as I said elsewhere in another reply to this article. I am not a biologist, please be kind if this question has an obvious, or easily googlable, answer.
-John
Re:Women already do this. (Score:5, Informative)
Re:Women already do this. (Score:3, Funny)
That would be a pretty freaky thing to discover about yourself. "Egad, I'm part female!" Gives a whole new meaning to, "getting in touch with your feminine side".
Re:Women already do this. (Score:4, Informative)
No. Most hermaphrodites have DNA for one person - not two distinct cell populations from two separately fertilized eggs.
Usually cases of "ambiguous gender" are the result of "testicular feminization", [nih.gov] ... genetically they are XY males, but because of an inherited trait on the X chromosome from their mom, they develop physically as female ... partially or to the extent that only their gynecologist could tell the difference.
The two I remember from doing lab tests in a fertility clinic were very "female" looking. And no, we didn't say "guess what, you are really a man" when the chromosome testing came back because they aren't. The default state for humans is female unless testesterone is produced by the fetus AND the fetus responds to it.
Y chromosome (Score:2)
Oh God... (Score:3, Funny)
Physical issues resulting from this? (Score:5, Interesting)
Re:Physical issues resulting from this? (Score:4, Informative)
Re:Physical issues resulting from this? (Score:3, Informative)
Re:Physical issues resulting from this? (Score:4, Funny)
I never realised she was a chimera!
Re:Physical issues resulting from this? (Score:4, Interesting)
Did an anomalous genotype contribute to his mental pathology? No obvious mechanism comes to mind.
Yes, this chimera assumes things go correctly (Score:5, Interesting)
Everyone has heard of Downs syndrome, when a child has an "extra" chromosome. Well, think of having twenty three extra pairs.
I am a fraternal twin, and I don't know if I am a chimera or not, but my wife and I have had trouble with a similar situation of too much DNA. Last year, we had a molar pregnancy.
"What is that?" you may ask. A molar pregnancy happens when an egg is fertilized, but no baby is formed. It happens when the egg "looses" the genetic information from the mother (complete molar), or has three sets of chromosomes (69 total, partial molar). Molar pregnancies are about 1 in 1500 births, with 98% of those being the complete type.
Either way, it is a horrific experience, and should be considered cancerous. The mother's hormone levels will climb to dangerous levels as the mass of cells that should have been an embryo rapidly grow and divide inside the womb. She will become extremely pregnant, without a child, and morning sickness becomes a 24 hour a day nightmare. Relief only comes with complete removal of all molar tissue. After this, the mother has to be monitored and be "pregnancy free" for a year, to tell if any of the molar tissue has become cancerous.
Our case was a partial molar. If things would have gone right, we would now have a set of identical twins, but it didn't. DNA is a funny and powerful thing and too much is never good.
-- Len
I **KNEW** it! (Score:5, Funny)
Chimerism doesn't create false positves (Score:2)
A Chimera would create a false negative, because the DNA extracted from the cells in the mouth would not match the DNA of the blood at the scene.
It might be a best practice t
Complications (Score:5, Interesting)
Wouldn't this cause complications a little more important to the individual than those listed? Like say, stuff not fitting together right? I mean, I wouldn't want to try and build a working car from half Ford Explorer parts and half Ford Focus parts.
I wonder how many people with this condition die before birth or at a very young age.
Re:Complications (Score:3, Funny)
Written by W. Kemp
Recorded by Johnny Cash on 3/5/76
Number one - County Chart; Number 29 - Pop Chart
Well, I left Kentucky back in '49
An' went to Detroit workin' on a 'sembly line
The first year they had me puttin' wheels on cadillacs
Every day I'd watch them beauties roll by
And sometimes I'd hang my head and cry
'Cause I always wanted me one that was long and black.
One day I devised myself a plan
That should be the envy of most any man
I'd sneak it out of there in a lunchbox in my hand
Now ge
1 Car, 1 Part Source (Score:5, Interesting)
There is a problem though with the immune system. Since each organism's cells contain a unique combination of cell surface receptors that let's their body know the difference between "self" and a bug or virus, then depending which copy of DNA founded the cells of the thymus (where "self" is first determined), a chimera's immune system could see cells with the other DNA set as foreign - causing a massive systemic allergic reaction. The good news is that chimeras with this problem would spontaneously abort within the first few months of the pregnancy, so if a chimeric human is born, they probably don't have to worry to much about such genetic mismatches.
Re:1 Car, 1 Part Source (Score:4, Informative)
Re:1 Car, 1 Part Source (Score:3, Informative)
Re:Complications (Score:3, Funny)
And the motor turned out to be a '73
And when we tried to put in the bolts all the holes were gone.
So we drilled it out so that it would fit
And with a little bit of help with an A-daptor kit
We had that engine runnin' just like a song
Now the headlight' was another sight
We had two on the left and one on the right
But when we pulled out the switch all three of 'em come on.
The back end looked kinda funny too
But we put it together and when we got thru
Well, that's when we noticed that we
It's not uncommon (Score:5, Interesting)
Re:It's not uncommon (Score:5, Informative)
Another great article (Score:5, Informative)
Since you can't RT{F}A (Score:5, Informative)
[Genetic Mosaics] http://users.rcn.com/jkimball.ma.ultranet/Biology
Google search for Genetic Mosaics [google.com]
And for the non-biologists [uiuc.edu]
Re:Since you can't RT{F}A (Score:4, Interesting)
To quote the nature article that's been mentioned several times here:
Mosaicism is more common than chimaerism and is also better studied. Human mosaics arise when a mistake during cell division in the early embryo stops the correct number of chromosomes segregating to each cell, or creates a mutation in a single gene.
Chimaerism, on the other hand is "people carrying tissues that originated in two separate embryos."
Worst. Joke. Ever. (Score:3, Funny)
However, before the launch of Safari [apple.com], I was using Chimera [mozdev.org], a descendent of Mosaic [uiuc.edu].
Told ya. Worst joke evar.
criminal uses? (Score:4, Interesting)
Interesting phenomena in itself, but I wonder if there are people who would (or already) exploit this sort of pseudo-anonymitity. Does anyone know how far this dual-DNA goes? can individual hairs have differing DNA? or will the blood have different DNA than the hair or skin? (I am not a biologist, so please be kind regarding these questions)
-John
Re:criminal uses? (Score:2, Informative)
RE the Ford assembly issues discussed above, no problem at all unless the genomes conflict (i.e. one is saying "we're male" and the other says "we're female") - we're talking adaptive self-assembly here, the parts remake themselves as necessary. If you have a functioning immune system you're partly chimeric anyway, as (the short version) your immune cells mutate themselves randomly to be able to e
Does this mean... (Score:4, Interesting)
Could he/she then sue their sibling for attempted murder?
Re:Does this mean... (Score:2)
Instead of hitting the link in in CA (Score:3, Informative)
No need to slashdot when the show is still available over the air.
Re:Instead of hitting the link in in CA (Score:3, Insightful)
What about transplant patients? (Score:5, Interesting)
so the answer is (Score:2, Insightful)
hair, blood, cheek, and perhaps ejaculatory(if it is a male)
then compare them, if they al match, then the DNA should be considered accurate.
Account for people with misshapen bodies? (Score:3, Funny)
Probably not, but there's got to be an explanation for this phenomena.
Re:Account for people with misshapen bodies? (Score:2)
I believe that sort of thing is usually due to problems in the hormonal growth regulation system.
Re:Account for people with misshapen bodies? (Score:5, Interesting)
Re:Account for people with misshapen bodies? (Score:3, Funny)
Now my stilt-man career is over!
Bone marrow transplants (Score:2)
It seems like they'd make a Law & Order or CSI episode from this: a career criminal arranges to get a bone marrow transplant from someone whose DNA is known to authorities, but who hasn't yet been apprehended (ooh, big word!). Then, the real bad guy can leave all the blood he wants at the crime
The Innocence Project (Score:4, Interesting)
In light of this article, I wonder how many guilty people have been set free. I'm sure there are guilty parties that proclaim their innocence and see no harm or foul in having the DNA testing done by said non profit organization, in hopes of some fluke in their favor.
Micheal Jackson now makes sense (Score:5, Funny)
MOD PARENT UP! (Score:2)
Re:Micheal Jackson now makes sense (Score:4, Funny)
Re:Micheal Jackson now makes sense (Score:4, Insightful)
So it is with some reluctance that I have to be a wet blanket... I know a sweet little girl who suffers from the same pigmentation disease as Jackson. It is called vitiligo, and although not health-threatening, it can be somewhat difficult for children who get labeled as "different" because of the light splotches that appear on the skin, and then spread. When it grows to cover more than 50% of the body, many opt to bleach the remaining <50% so that they are at least all one tone. I believe such is the case with Jackson.
Of course, it doesn't help that Jackson is a freak in many other ways, but there are thousands and thousands of people in this country, many of them children, who suffer from this condition without being freaks in any other way.
They are lucky when compared to the diseases that afflict many other people, but the disease is relatively unknown, so I thought I'd add a few words here in their defense (but not in Jackson's -- he's on his own :)
problem with NPrs explanation (Score:2)
Chimera embryo would not survie due too much body rejection of the parts of body that has the different dna..
The only case where thsi cannot happen and regualr occurs is the difference between human cell dan..or human genome nuclear and mitochrondia dna which produce no antigens but is diferent from the nuclear dna in that is the mother inherited mitochroindia dna form mother of the
Re:problem with NPrs explanation (Score:5, Interesting)
This is why people are interested in freezing fetal blood samples; the theory is that you keep a backup of the immune system install media to reinstall if it goes bad. Um, except that we have no idea how to do that yet... works in theory, though.
Maybee the story of (Score:2, Interesting)
Couldn't find any pictures (Score:2)
Inherited? (Score:2)
Twin Chimeras (Score:5, Funny)
another story of twins merging. (Score:3, Interesting)
Here [bbc.co.uk] is a pretty freaky story of a boy who seems to have assumed his twin in the womb. No one knew until when,at age seven, he had a stomach ache and surgeons removed his brother.
Doctors can't leave us alone. (Score:5, Interesting)
For many of us born this way we don't appear to be completely male or female and like most I was surgically "repaired" very soon after birth. This means I had what appeared to be testicles removed, testicles which MAY have permitted me to have children one day. Part of my body was stolen because I looked different. I was raised female, always felt that didn't quite fit, and it took me a lot of messing through courts to obtain my birth records. As I am now I have to settle with knowing where I fit originally, why I am like I am, and can accept living as a mostly normal female. By nature however, I was born part male part female. That's me. The chance to live and develop naturally was stolen from me.
It's fucked. Science continues to find so many variations on human development but society so often manages to force decisions on people. How odd that I was considered unnatural enough when I was born that doctors decided surgery was the only acceptable option, when my birth and very existence is just one more facet of nature.
For more info on how intersexed kids (chimeric or any other variation) are treated, see isna.org [isna.org]
Re:Doctors can't leave us alone. (Score:3, Interesting)
I think it's quite possible that it's an attempt to cover up realities that fly in the face of some people's interpretation of the Bible-- all that supposed Biblical prohibition of homosexuality and that defense of marriage stuff is dependent on the erroneous assumption that everyone is either 100% male or 100% female. I've heard some people try to write it off because the number of intersexuals is supposedly very small-- as if you can just ignore their existence because there aren't very many of them (whi
More information on Chimeras (Score:4, Informative)
http://users.rcn.com/jkimball.ma.ultranet/Biolo
And another genetic anomaly heard from (Score:5, Informative)
Normal male = Xy (any extra "X" are abnormal, but even a XXXXy is still male - all but one X gets deactivated - but usually has serious medical problems). Normal female = XX (extra "X"s do not create supermodels, it creates medical problems)
Take a look at any calico or tortoise shell cat. What you are seeing is the result of random deactivation of one of the X chromosome early in the development of the embryo, and the random appearance of the colors (black or orange) on that chromosome. Humans have few easily testable traits that are testible for chimerism: one blood group is all I can think of at the moment, that "lives" on the X chromosome.
For calico or tortie males (yes, they exist, and no they are not valuable) the division between the colors is a good indicator of how badly screwed up their sex chromosomes are. A male that is mostly orange with one small black patch probably acts like a tomcat and will show very few cells of the XXY pattern, and might even have that abnormality limited to that spot. One that is well-mottled with black and orange is probably not interested in breeding and will show mnay more abnormal XXY cells.
In order to test this for the possibility to screw up DNA identification, they could start by testing the known chimeras - cats.
A Tetragametic Human (Score:3, Informative)
Genetic Mosaics [rcn.com]
The writer discusesses a tetraparental mouse and a tetragametic human.
Re:For some reason... (Score:5, Funny)
Re:The Chinese and population control (Score:2, Insightful)
But what in the name of Hawking are you babbling about?
Re:Different Colored Eyes (Score:3, Funny)
Re:This Raises Some Interesting Questions.. (Score:3)
Re:Oh, great... (Score:3, Funny)
Yeah, I heard Donald Kaufman already picked this one up.
He will be hard pressed to beat his blockbusting "The 3" [imdb.com] though.