The most distressing part of all this is that the citizens of the United States have come to love liberty so little that when a agent of the state wants to fuck them with a sample swab, wants to remove a part of their living body, they won't fight.
Can you imaging the response of Thomas Jefferson or George Washington to the government demanding tributes of flesh from citizens?
The sovereignty of the government ends at my skin. You want a DNA sample? Get a warrant and see what you dead skin you can find in my bed (the samples with the Y chromosome are mine, guys), or arrest me and give me a bucket toilet and pull a sample out of my shit. But I will not voluntarily give up even a microgram of living flesh to the government. Yes, they'll probably get able to get a lot of samples out of my blood on the floor after they beat me, but I'll mix as much of theirs with it as I can. I will not let the government inside my body, and this is a bright and clear line I will fight for.
I'm not a Christian, but I always liked Jesus's line about the separation of church and state: render onto Caesar what is Caesar's, and onto God what is God's. My body does not belong to Caesar, and I will render no part of it onto him.
So, yes, if it comes to that: you can have my DNA when you extract it from my cold dead hand.
My concern is localized optima in what the public thinks of as nearly 'random' data. Consider a community of 20-40 thousand that is economically and culturally semi-isolated. Like a farming town - or a city ghetto. Yes, a ghetto in the middle of a city of millions can be semi-isolated genetically. How many people who can afford to live elsewhere will go to the poorest part of town to find a mate? How many people living there are able to get their "genes" out of the ghetto? After 100 years, just how 'rare' are the genetic markers found inside that community? (Some of these places have been that way since the civil war!)
Any sort of study to find the answer would have very loud political repercussions, thus is unlikely to ever be done (or been done - we'dve heard about it).
The odds may be millions when compared to the entire polpulation of a region, but can not be known without mapping the genetic clustering. The numbers may be much, much lower inside genetic clusters.
Without knowing how to account for genetic clustering and localized optima, the actual rarity of genetic markers in a specific case can not be known. And the difference will always favor the police by producing false positives.
After a few years of collecting DNA from the poorest, the police may be able to link any crime with someone in that community if 'familial' relationships are used as indicators. I've never seen *any* comment in articles about forensic DNA testing that discusses this.
Which is why, if on a jury, I will almost certainly disregard any DNA evidence.
Now add to that the real danger of DNA being a silver bullet. How many hairs have you lost, do you know where they have all ended up? Have you used tissues in a public space and carelessly failed to keep track of the discard. Next time you spit consider where it might end up.
Now as it turns out suspicion does not fall on family members with near matches but on untested family members. So if you are the one family member with a near match, they do not pursue you but they pursue all your untested relatives who now must prove their innocence.
Law enforcement will try to use a familial DNA match found at a crime scene as probable cause for a search warrant. It will happen. There are several scenarios. Imagine you have two brothers and you live in the same town, and brother 1 has been convicted of armed robbery. DNA at the crime scene of another robbery with a similar location to brother 1's first armed robbery is found that has a familial match to his DNA. A DA or detective would love to be able to use that as probable cause for a search warrant of your house and brother 2's house as well. Whether it would be granted depends on many factors. If you and brother 2 were suspected of being accomplices in the first armed robbery (say, letting him keep money, etc at your house) but never charged b/c of lack of evidence, you can be sure that would increase the chance of the warrant being granted.
The potential for abuse of this is off the chart.