What I was surprised to learn is that even fingerprints contain DNA, not just bodily fluids.
"The researchers found that archived latent prints indeed contained DNA and, using optimized methods, they were able to recover at least a partial DNA profile 90% of the time. One sample even produced a full profile."
>What I was surprised to learn is that even fingerprints contain DNA, not just bodily fluids.
A single skin cell contains all your DNA. However it's not enough to sequence. Call me an old cynic, but this smells like parallel reconstruction to cover up the real story.
How do you ensure that you don't amplify the wrong sample? That would seem to be the crux of the matter, especially for a sample from a fingerprint. Seems like most of the time you'll end up sequencing non-human DNA, given the disgustingness of the biological environment.
EDIT: ...or another persons DNA. Note that in general you aren't sequencing against a desired match, but generating a target for some future sequence (obtained from a suspect) to match against.
If you take a sample at a crime scene and its a match to your suspect, then there's no question what it is. If you sequence non human DNA you won't get a match. If you sequence the forensic lab technician's DNA by accident when taking the fingerprint sample you still won't get a match to the suspect.
PCR can make things up when it goes wrong, which can be as easy as getting the acidity wrong (acidity will cut DNA, which will then recombine into new sequences randomly, so will UV light. Both of these factors, you can bet your firstborn, were present in the sample). PCR (the kind used for sequencing, not the kind used for identification of viruses) does not fail when it is not given DNA or when it's given somehow bad DNA, as everyone in a microbiology lab has probably experienced, it just makes things up. If there is any DNA in the sample to trigger PCR to start, it will "finish". Just ... potentially with a lot of made up endings.
Given what exactly DNA is, and how this was collected, the odds of errors external to the testing procedure itself is pretty damn high (tiny sample, contaminated by loads of frankly incompetent people (police, whatever else you think of them, can seriously improve handling of samples. I'm not even arguing foul play here), contaminated/partially eaten by bacteria, irradiated by UV (which first mutates, then destroys DNA faster than you can say skin cancer), then this was inserted into a database with millions of samples.
Oh, and labs have a financial incentive to make this evidence stick.
Then the output: sequences are a LOT of high probability guesses (millions). So you will never have a 100% match between a sequence, as in a string, and a sequence you found. The output of gene sequencing is not the full genome, but a large amount of short sequences that don't quite fit, but almost, where an algorithm then extracts what might be called "globbing pattern" (if DNA is AGCCAGCAATA, the match might be AG?CA*AAGA (note the mistake at the end T->G). Yes, this is exaggerated, and yes, there's no '*', there's a special marker for "up to X letters missing here", where X can vary).
Important: these patterns contain mistakes. There are ZERO actual DNA sequences that match the output of sequencing. That's where probability comes in.
You do not get the actual sequence (although a "highest probability" match without ? and * can be produced, with the very important caveat that it's a guess with not all that high a probability. That's why they probably matched by matching the "globbing patterns" from samples in the database vs the evidence and then selecting the highest number of matches, rather than comparing an actual DNA "string").
One very relevant question to ask is "what was the probability of this match and what was the probability of the second best match?" (because it's going to be something like ~85% for best match and 75 or more for second best match, and there will be 100+ 20% matches)
And then there's the statistics problem. The police will focus on the odds that THIS match, BY ITSELF, happened. But this is not one match! This is the outcome of millions of matches! The vast majority were negative matches, and then a few hundred/thousand partial matches. That's how the misdirection works. The correct question to ask is "what are the odds, given a true negative rate, of a match if there shouldn't be a match?".
Why? Let's calculate: true negative rate 99.999%, a million people in the database. Odds of a false positive? 1-(99.999% ^ 1000000).
The odds of them fingering a random suspect when there is no positive match is thus: 99.99546023401903%.
As you can see, the more people in the DNA database, the less you can trust the results. Of course, you cannot, honestly, sidestep this problem by checking 10 databases.
This DNA match can be a starting point for an investigation. It is not valid evidence, despite the reputation DNA has. But you can bet anything the prosecutor will attempt to use DNA evidence as the word of God in a trial.
And where there is no question about at all, is that the police used people's DNA (not the murderer's) for something those people have never given ...
how can there be a wrong sample? if the sample leads to someone that they can prosecute, it can't be wrong. only guilty leave DNA samples at crime scenes. this is known.
Pretty sure this is sarcasm, but for general interest I'll mention the Phantom of Heilbronn (https://en.wikipedia.org/wiki/Phantom_of_Heilbronn), "responsible" for multiple murders, but really just an employee at the company that made the cotton swabs that got used for DNA collection.
PCR will only amplify DNA that exists in a sample. If you get a partial sample, running it through PCR will just give you more of what you already have. Helpful if you need a specific concentration of DNA to run an assay but not helpful otherwise.
It is possible to link a person to a partial DNA sample with something like patterns in SNPs but PCR won't help you create a full genome from a partial one.
Not sure if OP was misspeaking when they said "not enough to sequence" but they may have meant, not enough DNA to get a definitive match with the database samples.
Ironic that the original purpose of fingerprint matching itself is subjective pseudo science, just like bite mark comparisons, ballistic comparisons, and shoe and tire prints. But that doesn't stop them from being used.
I don't know how true it is but I've heard that they haven't done any studies to find out how likely it is that two people have the same prints. I have also heard that there is no objective criteria for things like number of matching points to determine a "match". But maybe the original commenter has additonal info, or other people have info to refute it.
The only things I can think of is that partials can match other fingers’s fingerprints and the temporal aspect —when was the print left, in the act of committing the crime or before or after?
Still it’s not pseudoscience like lie detectors, bitemark and bloodsplatter analyses.
Speaking as a non-expert, it sounds too good to be true with the regular reports of false-positives and false-negatives from DNA testing. I'm with this person: They did something illegal to save lives.
It seems reasonable that DNA evidence should not be used to convict someone alone, but if it's used as a starting point to find other evidence, well and good.
Couldn't that other evidence be perfectly legal but not publicized yet?
"Think of it this way: There are many thousands of paintings with blue backgrounds, but fewer with blue backgrounds and yellow flowers, and fewer still with blue backgrounds, yellow flowers, and a mounted knight in the foreground. When a forensic analyst compares alleles at 13 locations—the standard for most labs—the odds of two unrelated people matching at all of them are less than one in 1 billion." 1
In the past, there were issues with not getting these 13 sites sufficiently covered and losing statistical power. Today, to get around issues of certain markers dropping out for different reasons and to continue to ensure high statistical power, the FBI uses 20 markers now and samples must have a sufficient number of markers covered to be considered. 2
> the odds of two unrelated people matching at all of them are less than one in 1 billion.
Sounds like on a world with 7 billion people for each crime there are on average 7 people that can be convicted using the incontrovertible evidence delivered by the DNA lab.
Sorry, if the chances are one in a billion, and there’s 7 billion to choose from it’s actually not rare at all. That’s why you should be very careful to either use this kind of evidence either to find a suspect or as proof, and not both. But I’m sure we all know there’s plenty of ‘tough on crime’ judges that wouldn’t care about convicting someone based on this kind of seemingly rare occurrence.
Every piece of evidence presented in the court room has some probability of implicating someone else. That's why multiple pieces are generally presented.
You won't be collecting a single skin cell though, you will be collecting millions in that speck and there's plenty of redundancy there. Plus you don't need to cover the entire genome, just some variant sites that can give you enough statistical power to be confident in the identity of the sample.
Was the article headline updated to include the “Police say”? Because it’s good to see that police statements aren’t just accepted as fact and also need to be verified
An obvious question that perhaps has been researched - I'm curious how many different individuals' DNA would normally be found using current methods at a given site? Surely they don't just take a sample from a likely location and assume it's the perp?
There was a case a couple years ago in Santa Clara county where the DNA of a hopeless drunk that a paramedic treated ended up under the fingernails of a murder victim that the paramedic also treated a couple hours later.
> Think bigger: just being an enemy of an unfriendly state, potentially in your own country 25 years hence, who knows?
I don’t understand the logic of the supposed threat you’re talking about: if you’re so worried about some future dystopian authority that throws its ‘enemies’ into prison without them committing any crime, why would they need a relative’s long-ago stored DNA to do it?
The ancestry databases (at least, the ones I'm aware of) contain SNPs and not full genomic sequences. Even if "targeted assassination virus" was a real thing, it would almost certainly need more data.
Seems like a lot of work when a bullet or dioxin is much cheaper. In any case, if they really wanted to off someone with a targeted genetic attack, surely they could just swipe their DNA from a door handle, or a piece of mail, or a piece of trash carelessly thrown out, or from their sewage line, or a million different ways.
Sure they can make evidence up, but the logic is that even authoritarian regimes need an inner circle of honest supporters. Think CCP or USSR, they do honestly believe in what they do was right.
Here’s a bigger thought. Imagine a world where serial killers get caught a lot earlier before killing scores of people. The government is not the only enemy.
What I'm more worried about is insurance companies using this info to say you are part of a cohort expressing allele group X% and is thus more likely to Y, and then acting accordingly based on that info. What if in the future your grandchild gets told they express an allele that gives them a propensity to alcoholism, and on those grounds is barred from entering certain establishments without losing coverage, or without permission? It sounds outlandish, but it's not when you consider in some of our lives, we were born able to buy alcohol at any age, then 16, then 18, then 21. Recently in the past 5 years I've heard more than one conversation about possibly revisiting this to include smoking at age 21, and limiting the size of sugar drinks in a single purchase.
I don't consume sugar or alcohol, but it's also not my choice to say what you should do, especially not because of your genetics, yet if I were an insurance company we sign a contract that gives me that right, so why enable it?
>Genetic genealogy helped investigators identify the suspect, a source with knowledge of the case said. DNA found in Idaho was taken through a public database to find potential matches for family members, the source said. Once potential family matches were found, subsequent investigative work by law enforcement led to the identification of Kohberger, according to the source.
This article doesn’t elaborate and I’m not convinced their source(s) are accurate. There is a competing “source” from another news organization that is claiming they caught this guy when his phone pinged a “smart device” (Alexa or similar) and its MAC address was logged.
However from other cases where genealogy databases are used, typically what happens is once a DNA profile is developed, it can be compared with other entries in the public databases. If there are family members that exist in the database, you can develop a family tree from the known person and attempt to identify the target from public records. Typically the more distant the relative is from the target, the harder it is to come up with a family tree.
AFAIK law enforcement uses publicly available databases and not the private Ancestry or 23andMe DBs, which are thought to be much larger.
These aren't contradictory. You could have DNA id a subject and his phone provide a location, or DNA and the smart phone both point to the same person.
I agree they could both be used. For some reason I find it much more likely they caught him because his phone tried to connect to a device. But maybe I am giving too much credit to the tech surveillance dragnet.
Law Enforcement absolutely uses data from 23 and me and Ancestry
“ In certain circumstances, however, 23andMe may be required by law to comply with a valid court order, subpoena, or search warrant for genetic or personal information.”
While it might be true that 23andMe complies with court orders in specific cases, there is likely a distinction between individual subpoenas and carte blanche catalog access for law enforcement. I say this because a famous cold case in Philadelphia was recently solved with genetic geneaology and the researcher notes explicitly that law enforcement uses GEDMatch and not Ancestry or 23andMe for these cases [0]
The GSK case (California’s worst serial killer) was also solved through GEDMatch, and only public queries ie you can remove your profile from it if you care. To the extent that helps anything.
> There is a competing “source” from another news organization that is claiming they caught this guy when his phone pinged a “smart device” (Alexa or similar) and its MAC address was logged.
Link? I haven’t seen this story yet, but I am seeing the genealogy story reported in several places.
A home wifi that offers guest access through the provider like Comcast or ATT could cause that. I had my iPhone automatically connect to an ATT public access point against my wishes the other day. Beyond that, something like an airtag could have logged a connection, or some bluetooth device that happened to log all IDs it saw.
GSK was found because one of his third cousins had their DNA on GEDMatch. So, someone he shared a great-great-grandparent with. Based on GSK's age, that could mean the DNA uploader and GSK had a single common ancestor who was born in 1845.
Unfortunately, my in-laws did one of these services, which means my children are now potentially identifiable to some future unfriendly regime. This is a disaster for human rights advocates of the future.
What’s the use case here? A state wants to find all members of a certain family, so they get DNA from the population and compare against a genealogy database? Seems like there would be more straightforward ways to achieve this?
A bunch of people could be doing political activism at some location and be tracked down. Such scenarios don't seem too far fetched and the way these things will be abused in the future will probably be much more perverse, in ways we can't even imagine today.
> A bunch of people could be doing political activism at some location and be tracked down
Considering political activism is usually in groups out in the open, how practical would be to find the people participating via DNA tests (of what? maybe if they spit on the ground?), compared to the already existing and used phone geolocation and face recognition? Yes those can be protected against by not carrying a phone and wearing a mask/balaclava, but one can also take steps not to leave any DNA residue of use.
So I think it's pretty far fetched, and if you're concerned about your government abusing political activists (within reason of course, coup plotters are also technically political activists but not the type one wants to protect) there are better things to do than to focus on one specific impractical avenue of recognition that could lead to abuse.
They want to find who committed <some crime they just made up that isn't actually bad>, so they identify DNA and compare it against the known database.
This is pretty standard "how will we respond if there is a future authoritian regime"? (not saying the fear is unjustified - just saying the fear is pretty standard)
--------
Edit:
People are really misunderstanding my comment. Let me try again.
To be clear, this is hypothetical:
The government makes it illegal to support anyone of opposing political party. Which includes, not buying from their store. They go to the restaurant of the opposing party and run a DNA test on all of the silverware. They arrest anyone whose DNA matches the DNA on the silverware - because those people "supported" the opposing party.
I agree bit at the same time I would imagine authoritarian regimes wouldn’t care about the specifics of DNA when they can just use their absolute authority to imprison people.
To have evidence to pacify some of those still on the fence about the regime vs out right in favor? The anti-regime will always be anti, but if you can keep those undecideds pacified with attempts at evidence/fair trial, you can make it look like majority in favor
Of course, it's true an evil regime can just accuse random people of crimes and arrest them.
But it's much worse if they manage to identify actual critics, people who actually defied them in some way.
The regime that strikes out randomly, probably that ferments opposition, right? The revolution that eats its young is a lot less scary than the revolution that consistently eats its enemies.
It's not that people misunderstand you, it's just that your made scenario doesn't make much sense on multiple levels. What sort of party has a restaurant or a store, especially when in opposition to an authoritarian regime? What sort of authoritarian regime wouldn't just surveil/round up opposition as thet the usually do?
If there's a certain racial group that the government wants to get rid of, this would be a large help. See this article about how records of who is Jewish were important to the Nazis[1].
Although I'm not sure how likely this is to be an actual threat we face.
The East German Stasi kept thousands of “scent jars” so they could use dogs to track specific citizens. I’m not sure how effective DNA surveillance would be in this tracking role, but one could imagine future improvements in the technology that make it more feasible. https://www.spymuseum.org/exhibition-experiences/about-the-c...
The major (mis)uses would be faulty forensics where from human mistake, computer error, equipment failure, hash collision, procedural failure, or manufactured evidence. If the law is sane then there is safeguards that require independent proof of evidence beyond that of DNA, but in cases where they are desperate enough to go to genealogy databases there tend to be a major lack of independent evidence beyond of DNA.
They were always identifiable. If anyone ever even slightly cares about your DNA, you have no way of stopping them from getting it - you literally leave it everywhere you go.
On the other hand, solving actual crimes today has to be weighed against hypothetical future misuse by a hypothetical "future unfriendly regime". People have different beliefs about the probability of such a future, but to me it seems like this is a big win for society.
Actual crimes today are less than statistical error when compared to traffic accidents, obesity and the like. They are only overblown so you feel grateful to the state for solving them and dread what would happen without Big Brother.
And if the probability of that happening AND the genome database being necessary for that government to carry out it's murders is smaller than 1e-7, then the database is good. I think it's much smaller than that, essentially zero.
It's implausible to me that the existence of a gene database would matter. Historically it hasn't been necessary to carry out mass killings. I don't think science fiction is a good source for designing policy.
On the contrary, science fiction is an excellent resource for policy, as it imagines futures where certain policies are carried out to their final conclusions.
Which paper? The one pointing out that links are easy to determine with only a small genetics database? Why would I care about that, I want law enforcement to have (audited) access to 100% of the populations genetic records, so I'm not concerned about how small a sample is needed.
> While most people would agree that putting a serial killer behind bars is an acceptable tradeoff, questions are nevertheless growing about who should control the genetic data compiled by genetic testing companies and how that data should be used: Are we willing to give up our genetic information in exchange for more efficient law enforcement, health information, and consumer targeting practices?
History repeats itself. We have never had a technology like this, but we know humans have had multiple genocidal dictatorships whose tyranny slew millions. I damn well will scrutinize each technological achievement's ability to facilitate tyranny. You can frame it hyperbolic, but look at Twitter or Facebook. These platforms have become instrumental to governments for survelience and intelligence. Identifying the murderer is wonderful (absolutely not disagreeing) , but in my opinion society ought to be worried about personal freedoms and rights.
GSK was caught by 3rd cousins uploading DNA - your children probably have hundreds of relatives at that level.
Look on the bright side - at least if you children turn out to be murderers, they will be brought to justice more swiftly even if they're really careful about their crimes.
Yes there is a surprising amount of worry about serial killers in this thread, compared with authoritarian governments who have killed literally millions of times more people [than serial killers] in just the 20th century alone.
More like a disaster for human rights advocates today, as this is very much technology being used now.
But what's the alternative? If you assume mass surveillance techniques are illegal and not being used in the US, i would be ok with a DNA database that provides a loose correlation to other family members, if it's used for purposes such as this one. The lesser of two evils
It does make you wonder if it’s really valid consent that a person grants to one of these databases when the information they’re granting access to is shared by a group of individuals.
So it went: <DNA at crime scene -> <magic DNA database> -> <DMV database> -> White Elantra ??
Why didn't they just say "we're looking for this guy", vs "we're looking for a white Elantra"?
Any time I see LE seemingly making an unlikely breakthrough, I suspect they constructed the apparent evidence to cover up use of illegal mass surveillance tech. e.g. those times when the mass murderer "happens to be pulled over for having a broken tail light".
I think it was more parallel than that: while we’re running crime scene dna against genealogy dbs, let’s also look for hits on an a white Elantra at the scene. Notice they also said the Elantra was a dead-end last week, so at that point they probably already matched the owner with the dna and knew where they were.
Some more detailed reporting today reveals that you're probably right: they first identified the set of people or vehicles in the area/time. Then they collected DNA and cross-checked the DNA with the set of area/time suspects. That led them to the suspect. Everything after that was just waiting to see if he would incriminate himself further? or perhaps just to make the movie plot more interesting?
I'm pretty sure the white Elantra was a tip from the public and its discovery wasn't related to the DNA at all. IIRC, a night shift gas station attendant was going through tapes on the night of the murder to see if they could help and something about the Elantra stood out.
I don't see why it would be. The police have no obligation to share the "why" behind their thinking at this point. They could have just said, "we're looking for a white Elantra" and left it at that.
If they lied about where the tip came from that would likely come out during the trial and hurt the prosecution's case.
While some people have a moral objection to it, using DNA in the way they did is totally legal. If that was really how they got the tip, they gain little by lying about it, but getting caught in that lie would have a massive downside.
Nah geanolgy websites are very cooperative with law enforcement.
Males are extremely trackable with their Y gene since it's guaranteed to pass from father to son, along with the suspect being white (the race with highest level of participation in genetic genealogy, meaning you can find 90% plus indirectly somehow).
After you find the family line it's just records work and narrowing down based on region/age/motive. Followed by some dumpster diving on a handful of suspects.
My thinking was: if you put the entire resources of the USG onto the job, how hard is it to find a person who was at a specific location at a specific time, in a city? (even if they have good opsec and didn't carry a cell phone). Also: given same resources, how hard is it to find a White Hyundai Elantra in Eastern Washington/Idaho panhandle? It it were a white F-150, sure that might be hard. But there just aren't many white Elantras in that part of the world.
Genealogy is a network, so on a related note: I was reading the article and found a couple of the names interesting and distinctive, and did a cursory search — all of the victims have active social media accounts that are still publicly available for anyone to peer into. Ghoulish. If I was a parent I wouldn't even know where to begin with drawing the curtains over my late children's lives. Unless they wanted to leave some kind of living testament?
As an industry, we're not thinking about things like this, because we don't like difficult, nuanced questions.
I think Google and Facebook (and a few others, e.g. Bitwarden comes to mind) have dead man switches that can be enabled - if you haven't logged in for X time, your account will be transferred to a designated person.
Some people are commenting a lot about parallel reconstruction and such. Here are a few key points from a long time North Idaho resident and someone who has spent quite a bit of time in the town.
-DNA was probably used for sure to narrow things down...once you find any sort of special DNA grouping it shouldn't be too hard to narrow down even if you don't have a database with a hit (i.e. Pennsylvania dutch or similar). Then once you have an actual suspect...you find some garbage or discarded item and do a more direct test for certainty. But I suspect filtering by genetic markers and white Hyundai gets you a lot closer than it might seem.
-Some are skeptical about the car being randomly identified...but this town is very small. There are not a lot of entrances/exits from the area. When I saw the location of the murders my first thought was "this person could very well be living in Pullman" since the nearby road leads directly there. It is very hard to not be forced to drive past cameras or businesses when attempting to leave the area.
-Idaho (particularly North Idaho) took a considerable amount of the homeland security money 20 or so years back and spent quite a bit on license plate scanners, highway cameras...etc. You pass at least 3 license plate scanners I have seen just between Coeur d'Alene and Spokane. I suspect there are more of these we don't know about or are harder to see as well. If there was one of these on each of the 3 or so main routes in/out of town it would be very easy to add this to the list of ways they built the case.
-It would be super easy for this person to stalk these girls in the area. Lots of random people, college town, more than one of them worked in the restaurant industry. In the next few weeks I suspect there will be a lot more reports from the area about this person being around creeping people out while they were working.
-Also, I want to reiterate how small this town is. You can quite literally explore the entire town in a car within a half hour. Pullman is essentially right next door with little more than some fields and the state line in between. Pullman is equally as small. When the students go home...the town is very empty.
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[ 4.0 ms ] story [ 199 ms ] thread"The researchers found that archived latent prints indeed contained DNA and, using optimized methods, they were able to recover at least a partial DNA profile 90% of the time. One sample even produced a full profile."
https://nij.ojp.gov/topics/articles/dna-our-fingertips
A single skin cell contains all your DNA. However it's not enough to sequence. Call me an old cynic, but this smells like parallel reconstruction to cover up the real story.
I'm not sure what you mean by that. The nice thing about DNA is you can make more of it if you don't have enough. [1].
[1] https://en.wikipedia.org/wiki/Polymerase_chain_reaction
EDIT: ...or another persons DNA. Note that in general you aren't sequencing against a desired match, but generating a target for some future sequence (obtained from a suspect) to match against.
PCR can make things up when it goes wrong, which can be as easy as getting the acidity wrong (acidity will cut DNA, which will then recombine into new sequences randomly, so will UV light. Both of these factors, you can bet your firstborn, were present in the sample). PCR (the kind used for sequencing, not the kind used for identification of viruses) does not fail when it is not given DNA or when it's given somehow bad DNA, as everyone in a microbiology lab has probably experienced, it just makes things up. If there is any DNA in the sample to trigger PCR to start, it will "finish". Just ... potentially with a lot of made up endings.
Given what exactly DNA is, and how this was collected, the odds of errors external to the testing procedure itself is pretty damn high (tiny sample, contaminated by loads of frankly incompetent people (police, whatever else you think of them, can seriously improve handling of samples. I'm not even arguing foul play here), contaminated/partially eaten by bacteria, irradiated by UV (which first mutates, then destroys DNA faster than you can say skin cancer), then this was inserted into a database with millions of samples.
Oh, and labs have a financial incentive to make this evidence stick.
Then the output: sequences are a LOT of high probability guesses (millions). So you will never have a 100% match between a sequence, as in a string, and a sequence you found. The output of gene sequencing is not the full genome, but a large amount of short sequences that don't quite fit, but almost, where an algorithm then extracts what might be called "globbing pattern" (if DNA is AGCCAGCAATA, the match might be AG?CA*AAGA (note the mistake at the end T->G). Yes, this is exaggerated, and yes, there's no '*', there's a special marker for "up to X letters missing here", where X can vary).
Important: these patterns contain mistakes. There are ZERO actual DNA sequences that match the output of sequencing. That's where probability comes in.
You do not get the actual sequence (although a "highest probability" match without ? and * can be produced, with the very important caveat that it's a guess with not all that high a probability. That's why they probably matched by matching the "globbing patterns" from samples in the database vs the evidence and then selecting the highest number of matches, rather than comparing an actual DNA "string").
One very relevant question to ask is "what was the probability of this match and what was the probability of the second best match?" (because it's going to be something like ~85% for best match and 75 or more for second best match, and there will be 100+ 20% matches)
And then there's the statistics problem. The police will focus on the odds that THIS match, BY ITSELF, happened. But this is not one match! This is the outcome of millions of matches! The vast majority were negative matches, and then a few hundred/thousand partial matches. That's how the misdirection works. The correct question to ask is "what are the odds, given a true negative rate, of a match if there shouldn't be a match?".
Why? Let's calculate: true negative rate 99.999%, a million people in the database. Odds of a false positive? 1-(99.999% ^ 1000000).
The odds of them fingering a random suspect when there is no positive match is thus: 99.99546023401903%.
As you can see, the more people in the DNA database, the less you can trust the results. Of course, you cannot, honestly, sidestep this problem by checking 10 databases.
This DNA match can be a starting point for an investigation. It is not valid evidence, despite the reputation DNA has. But you can bet anything the prosecutor will attempt to use DNA evidence as the word of God in a trial.
And where there is no question about at all, is that the police used people's DNA (not the murderer's) for something those people have never given ...
Also your details about error rates in sequencing aren't correct either (you often get completely accurate reads of reasonable lengths).
It is possible to link a person to a partial DNA sample with something like patterns in SNPs but PCR won't help you create a full genome from a partial one.
Not sure if OP was misspeaking when they said "not enough to sequence" but they may have meant, not enough DNA to get a definitive match with the database samples.
Still it’s not pseudoscience like lie detectors, bitemark and bloodsplatter analyses.
Couldn't that other evidence be perfectly legal but not publicized yet?
"Think of it this way: There are many thousands of paintings with blue backgrounds, but fewer with blue backgrounds and yellow flowers, and fewer still with blue backgrounds, yellow flowers, and a mounted knight in the foreground. When a forensic analyst compares alleles at 13 locations—the standard for most labs—the odds of two unrelated people matching at all of them are less than one in 1 billion." 1
In the past, there were issues with not getting these 13 sites sufficiently covered and losing statistical power. Today, to get around issues of certain markers dropping out for different reasons and to continue to ensure high statistical power, the FBI uses 20 markers now and samples must have a sufficient number of markers covered to be considered. 2
1. https://www.theatlantic.com/magazine/archive/2016/06/a-reaso...
2. https://www.nist.gov/news-events/news/2016/12/nist-research-...
Sounds like on a world with 7 billion people for each crime there are on average 7 people that can be convicted using the incontrovertible evidence delivered by the DNA lab.
https://www.science.org/content/article/dna-pulled-thin-air-...
I don’t understand the logic of the supposed threat you’re talking about: if you’re so worried about some future dystopian authority that throws its ‘enemies’ into prison without them committing any crime, why would they need a relative’s long-ago stored DNA to do it?
So it's not exacly a slippery slope.
On the other hand there's clear benefits of DNA database now in catching murderers and the like. So a clear win.
I don't consume sugar or alcohol, but it's also not my choice to say what you should do, especially not because of your genetics, yet if I were an insurance company we sign a contract that gives me that right, so why enable it?
This seems unavoidable otherwise.
* (and that is completely okay, different strokes and all that)
I remember this story of a killer getting caught by his cousin’s DNA
>Genetic genealogy helped investigators identify the suspect, a source with knowledge of the case said. DNA found in Idaho was taken through a public database to find potential matches for family members, the source said. Once potential family matches were found, subsequent investigative work by law enforcement led to the identification of Kohberger, according to the source.
https://www.cnn.com/2022/12/30/us/university-of-idaho-studen...
However from other cases where genealogy databases are used, typically what happens is once a DNA profile is developed, it can be compared with other entries in the public databases. If there are family members that exist in the database, you can develop a family tree from the known person and attempt to identify the target from public records. Typically the more distant the relative is from the target, the harder it is to come up with a family tree.
AFAIK law enforcement uses publicly available databases and not the private Ancestry or 23andMe DBs, which are thought to be much larger.
“ In certain circumstances, however, 23andMe may be required by law to comply with a valid court order, subpoena, or search warrant for genetic or personal information.”
https://www.23andme.com/law-enforcement-guide/
[0] https://www.inquirer.com/news/philadelphia/joseph-zarelli-bo...
Link? I haven’t seen this story yet, but I am seeing the genealogy story reported in several places.
The End of Genetic Privacy in the Blade Runner Canon - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9731365/
They kind of do though.
> A bunch of people could be doing political activism at some location and be tracked down
Considering political activism is usually in groups out in the open, how practical would be to find the people participating via DNA tests (of what? maybe if they spit on the ground?), compared to the already existing and used phone geolocation and face recognition? Yes those can be protected against by not carrying a phone and wearing a mask/balaclava, but one can also take steps not to leave any DNA residue of use.
So I think it's pretty far fetched, and if you're concerned about your government abusing political activists (within reason of course, coup plotters are also technically political activists but not the type one wants to protect) there are better things to do than to focus on one specific impractical avenue of recognition that could lead to abuse.
This is pretty standard "how will we respond if there is a future authoritian regime"? (not saying the fear is unjustified - just saying the fear is pretty standard)
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Edit:
People are really misunderstanding my comment. Let me try again.
To be clear, this is hypothetical:
The government makes it illegal to support anyone of opposing political party. Which includes, not buying from their store. They go to the restaurant of the opposing party and run a DNA test on all of the silverware. They arrest anyone whose DNA matches the DNA on the silverware - because those people "supported" the opposing party.
But it's much worse if they manage to identify actual critics, people who actually defied them in some way.
The regime that strikes out randomly, probably that ferments opposition, right? The revolution that eats its young is a lot less scary than the revolution that consistently eats its enemies.
Uighurs in China. Communists in America during the McCarthy Era. Muslims in countries where "terrorism" is illegal.
Although I'm not sure how likely this is to be an actual threat we face.
[1] https://jacquesmattheij.com/if-you-have-nothing-to-hide/
https://www.kold.com/2022/09/29/dna-genealogy-led-arrest-pho...
Read the linked study in the comments on Blade Runner, Phillip K Dick.
Again, your view is unimaginative.
On the contrary, science fiction is an excellent resource for policy, as it imagines futures where certain policies are carried out to their final conclusions.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9731365/
> While most people would agree that putting a serial killer behind bars is an acceptable tradeoff, questions are nevertheless growing about who should control the genetic data compiled by genetic testing companies and how that data should be used: Are we willing to give up our genetic information in exchange for more efficient law enforcement, health information, and consumer targeting practices?
Yes, I am. It's worth it.
Your acceptance of this loss of autonomy will cost me my autonomy.
The benefit is to ensure punishment for a wildly unlikely, tragic thing occurring.
I think you don't understand what humans lose.
You're attacking straw men here.
Look on the bright side - at least if you children turn out to be murderers, they will be brought to justice more swiftly even if they're really careful about their crimes.
Again, I don't understand people who fear nameless nobodies over actually powerful people.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549546/
So it went: <DNA at crime scene -> <magic DNA database> -> <DMV database> -> White Elantra ??
Why didn't they just say "we're looking for this guy", vs "we're looking for a white Elantra"?
Any time I see LE seemingly making an unlikely breakthrough, I suspect they constructed the apparent evidence to cover up use of illegal mass surveillance tech. e.g. those times when the mass murderer "happens to be pulled over for having a broken tail light".
If they lied about where the tip came from that would likely come out during the trial and hurt the prosecution's case.
While some people have a moral objection to it, using DNA in the way they did is totally legal. If that was really how they got the tip, they gain little by lying about it, but getting caught in that lie would have a massive downside.
Males are extremely trackable with their Y gene since it's guaranteed to pass from father to son, along with the suspect being white (the race with highest level of participation in genetic genealogy, meaning you can find 90% plus indirectly somehow).
After you find the family line it's just records work and narrowing down based on region/age/motive. Followed by some dumpster diving on a handful of suspects.
As an industry, we're not thinking about things like this, because we don't like difficult, nuanced questions.
-DNA was probably used for sure to narrow things down...once you find any sort of special DNA grouping it shouldn't be too hard to narrow down even if you don't have a database with a hit (i.e. Pennsylvania dutch or similar). Then once you have an actual suspect...you find some garbage or discarded item and do a more direct test for certainty. But I suspect filtering by genetic markers and white Hyundai gets you a lot closer than it might seem.
-Some are skeptical about the car being randomly identified...but this town is very small. There are not a lot of entrances/exits from the area. When I saw the location of the murders my first thought was "this person could very well be living in Pullman" since the nearby road leads directly there. It is very hard to not be forced to drive past cameras or businesses when attempting to leave the area.
-Idaho (particularly North Idaho) took a considerable amount of the homeland security money 20 or so years back and spent quite a bit on license plate scanners, highway cameras...etc. You pass at least 3 license plate scanners I have seen just between Coeur d'Alene and Spokane. I suspect there are more of these we don't know about or are harder to see as well. If there was one of these on each of the 3 or so main routes in/out of town it would be very easy to add this to the list of ways they built the case.
-It would be super easy for this person to stalk these girls in the area. Lots of random people, college town, more than one of them worked in the restaurant industry. In the next few weeks I suspect there will be a lot more reports from the area about this person being around creeping people out while they were working.
-Also, I want to reiterate how small this town is. You can quite literally explore the entire town in a car within a half hour. Pullman is essentially right next door with little more than some fields and the state line in between. Pullman is equally as small. When the students go home...the town is very empty.