>My understanding is that DNA is basically unique, but the patterns use for conventional DNA analysis are not.
Even if they were, unless it's something like blood DNA after an attacker gets hurt, liquids from a rape, etc. it's trivial:
1) for the culprit to take another's DNA and place it on a crime scene
2) for an innocent to leave DNA at what would later be a crime scene
3) for police (or anyone with access) to add someone's DNA at a crime scene [1]
And the worst thing is, the DNA match then is considered "irrefutable" evidence...
[1] If you (3) is far-fetched, you haven't been following 100 years of police tampering to frame people, even in the USA, and much more in places like Latin America, etc. Just two recent examples:
Even if they were, unless it's something like blood DNA after an attacker gets hurt, liquids from a rape, etc. it's trivial:
1) for the culprit to take another's DNA and place it on a crime scene
2) for an innocent to leave DNA at what would later be a crime scene
3) for police (or anyone with access) to add someone's DNA at a crime scene [1]
And the worst thing is, the DNA match then is considered "irrefutable" evidence...
[1] If you (3) is far-fetched, you haven't been following 100 years of police tampering to frame people, even in the USA, and much more in places like Latin America, etc. Just two recent examples:
https://www.buzzfeednews.com/article/melissasegura/detective...
https://www.huffpost.com/entry/baltimore-cop-drug-video-indi...