> Where does the database come into this?

"The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person." [0]

[0] https://www.nytimes.com/2009/08/18/science/18dna.html

> if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile

Oh wow. Really??? Any experts in this field reading this? Would love to hear someone with pertinent authority tell us this isn't true. (Please don't be true)

It is simple to do, assuming the police are using genotyping instead of a full genome sequence for the match. (This is the common case today.)

Genotyping works as follows: there are thousands of regions of “junk” dna in the human genome that don’t code for anything. There is no evolutionary pressure to preserve the exact length of these regions. (They probably help the chromosomes fold up in ways that encourage/suppress the activity of certain genes, help the molecule be more robust, etc).

Since there is no evolutionary pressure to preserve the regions, they tend to be full of hard to copy junk like ATAT..... that tends to change every few generations.

Genotyping works by isolating a bunch of these regions, and using PCR to create millions of copies of each region (with ~one sample per region).

Finally, you put a drop of the each sample and some die on a electrophoresis gel, and apply some current. Different sized molecules move at different rates, so this gives you a crude measurement of the length of each molecule.

To fake a match, all you need to do is produce something that will trick the first step of all this into grabbing molecules of your choice of length, which will fool the rest of the process. If you want to see how that would work, read up on “pcr primers”.

Source: I used to work in a genotyping/sequencing lab as a bioinformatician, and worked on algorithms that did exactly this sort of analysis (not the forgery bit though).

Hey, that's just like fake video.

So you could fake everything. Video surveillance, DNA samples, testimony from dishonest informers and investigators, etc. This is just a tweak to parallel construction. And outright framing.

DNA is supposed to be supporting evidence of guilt (A number i've heard thrown around is it narrows down to 1 in 1m, with >300m people in the US that is still not perfect).

Instead CSI has taught your average juror that it is irrefutable proof of guilt.

There links in that NY Times article and they look like reasonable sources.

> Surely you would need to place that suspects DNA at the scene

Don't underestimate DNA transfer. Your DNA can end up in locations you have never been:

https://www.wired.com/story/dna-transfer-framed-murder/

Right now you do not have a convenient way to force your target to submit to a DNA test. This way you can frame someone by placing their DNA at the crime scene and then having it "discovered" using DNA testing company data.

Because there is a line when framing people never to be crossed ;) come on throw in a shoe print,a witness, fake signature. something extra

Just because the government finds your DNA at the crime scene doesn't mean they know it's yours. They have to match it against some sort of database that connects the DNA to your identity.

There's a case against globally accessible DNA databases from the point of view of dragnet approaches picking up people whose connection to the crime scene is either totally incidental or actually nonexistent and purely down to data mixups, but that's a largely separate issue from authoritarian police trying to massage the evidence in a case against a particular person.

If you're already a "convenient suspect" the police wish to build a case against, they don't need to find you on a consumer genetics database to be able to obtain a sample of your DNA or strongly hint that they expect to be able to use DNA evidence (truthfully or otherwise) to send you away for a very long time if you're not willing to consider moving to plea bargaining territory.

With enough corruption, they might also "find" it on the crime scene.

Exactly, while DNA may identify an individual with high precision, we have to trust that that DNA was actually associated with the location or event.

Consider a public bathroom: how much DNA is at that location? How much is relevant to the event?

Consider a corrupt lab tech: The DNA at the event might be reported as DNA from their database. Does a defense attorney get to see the untainted sample?

Consider a corrupt/hacked DNA database: The database might report that the DNA belongs to one individual when it actually doesn't. Does a defense attorney even get to see the source code?

In these scenarios, the link to any individual is either of little consequence, or fraudulent.

And in case this sounds implausible, a corrupt lab tech handled 60,000 cases in MA:

https://www.cbsnews.com/news/annie-dookhan-chemist-at-mass-c...

With Pcr you’d only need a very small sample to produce enough DNA to smother a crime scene in “evidence”