Reading Today’s Question on identical twins having the same DNA or not , have any scientists actually found people having identical DNA’s . I see this program called Medical Detectives on Discovery Channel , giving all the probablities of people having the same DNA and about a million , billion to one etc. So its possible rite?Are these clones?
Link, Please?? 
I doubt it seriously simply because it would cost so much to run tests, etc. I’ve had people say that they saw someone that looked exactly like me (poor things), but I’ve never seen them and have never had my DNA tested. I believe that the statements you mention are based on statistics. If I were to hunt for my statistical twin I could try doing it by illimination and the first person I would illiminate would be Michael Jordan. [list][list][list][list][list][list][list]
Would the second one you illiminate be the winner of the National Spelling Bee? 
Granted this comes from a rather dubious source, however…
On one of those programs where the gal goes on and says “One of 27 different men could be the father of my child, please give them all paternity tests.” and then weeps uncontrolably when the true father is announced, there was a gal who had slept with twin brothers.
Paternity tests were given to the brothers and the paternity experts couldn’t determine who the father was because the results were identical.
I spose that means that their DNA is identical as well, but it was Maury Povich or something that I saw it on. (HEY - I was on vacation - brain candy was absolutly necessary)
IANAScientist, but I think there’s a difference between someone having identical DNA to you and someone appearing to match you on a ‘DNA fingerprint’ test; the test involves using enzymes (or something) to chop up the DNA into fragments; these are then forced through a gel by applying an electric current; the smaller fragments spread out quicker than the larger fragments and eventually, after processing, the characteristic ‘DNA barcode’ can be observed, but this isn’t a test of how the DNA is actually coded, it’s just a test of what size fragments it chops up into; sure, there’s going to be a correlation between the two, but it ought to be possible to obtain similar-looking results from people with different DNA.
Then again, maybe I’m talking out of my arse, so feel free to correct me if I’m wrong.
It is extremely unlikely that scientists would find 2 individuals with the exact same genetic makeup (except twins of course). There are too many possible combinations of nucleic acids. When you see people discuss the probability of 2 people having the same DNA what they are usually talking about is the probability of their having the same sequences at a given number of test sites. If any of the test sites do not match then the DNA is not the same. If all the sites match then the DNA could be the same, but since the entire sequence of the genome was not determined and matched there is the possibility that only matching sites were checked and non-matching DNA is elsewhere. This is where statistics come in. The statistics give the probability that 2 people could randomly have the same sequences at the same tested sites.
I hope this is as clear to the reader as it is to me.
John
IANAScientist, but I found this article on DNA testing. I noticed this test described doesn’t determine whether two people have exactly the same DNA sequence, only whether the lengths of certain fragments are the same. Since not all DNA fragments vary in length from person to person, two people could have identical test results, even if their DNA was (very) different.
I wonder if the Discovery channel was quoting the odds of matching test results, or of actually having an identical sequence.
Wouldn’t matching the exact sequence of two people be equivalent to mapping the entire human genome, twice?
LMAO, good one johnson
Thing 1
Sorry, I didn’t see your answer until after I posted. I didn’t mean to echo you.
So what would be the statistical chance that two sibs, not identical twins, could have the same DNA? Since their DNA is a combination of genes from the same Mom and Dad, their chances would be much higher than for two people chosen at random. But I’m guessing the odds are still astronomically against it.
Yup, you’ll have to sequence and match all 3 billion bases for two people. This is a non-trivial undertaking, although not impossible - the various human genome mapping projects have sequenced at least 10 individuals between them, IIRC. One thing to consider is that sequencing is not an error-free process. Even if your error rate is 1 in a million bases, that would still leave you with 3000 bases that you got wrong. Actual error rates tend to be considerably higher.