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How much of a population’s DNA needs to be mapped before you can reliably triangulate the the identity of any individual by comparing to known DNA profiles? For

by Tycho 8y ago

How much of a population’s DNA needs to be mapped before you can reliably triangulate the the identity of any individual by comparing to known DNA profiles? For instance if I have two cousins on different sides in the database, can they look at my DNA and narrow down the possible matches to me and my siblings of the same sex? What about more distant relations? (I’m thinking about how police caught that serial killer recently because some of his relatives had used one of these sites)

ssnistfajen 8y ago
It has sort of happened already: https://www.scientificamerican.com/article/how-to-identify-almost-anyone-in-a-consumer-gene-database/ https://www.scientificamerican.com/article/how-to-identify-a...
Real_S 8y ago
This depends entirely on the population. Rare individuals with unique DNA markers are easier to re-ID than individuals with more common DNA markers. But also consider that ethnicity is relatively easy to get from genetic data. So individuals with unique ethnic combinations can be trivial to identify by their genetic data. Now consider that genetic data can also be used to predict traits such as height, hair color, eye color, etc [0]. Reliable triangulation is already possible, and becomes increasingly more accurate as more data becomes available. 0: E.g.this company- https://snapshot.parabon-nanolabs.com/ https://snapshot.parabon-nanolabs.com/
gwern 8y ago
Very roughly, ~2%: https://www.biorxiv.org/content/early/2018/06/19/350231 https://www.biorxiv.org/content/early/2018/06/19/350231
dangrossman 8y ago
That's how a local cold murder case was solved. DNA from a 25-year-old crime scene was run against a genealogy database, and found a familial match. Police set up a sting to obtain DNA from that person's relatives. They found a DNA match with the brother's water bottle taken from the trash. The brother had never submitted a DNA sample to any databases himself. https://lancasteronline.com/news/local/christy-mirack-s-slaying-solved-with-arrest-of-lancaster-county/article_f05a2ee4-78b2-11e8-ad10-4382ef42f96d.html https://lancasteronline.com/news/local/christy-mirack-s-slay... The alleged killer was the DJ at my wedding. The trial's in May.

by Tycho 8y ago

ssnistfajen 8y ago

It has sort of happened already: https://www.scientificamerican.com/article/how-to-identify-almost-anyone-in-a-consumer-gene-database/ https://www.scientificamerican.com/article/how-to-identify-a...

Real_S 8y ago

This depends entirely on the population. Rare individuals with unique DNA markers are easier to re-ID than individuals with more common DNA markers. But also consider that ethnicity is relatively easy to get from genetic data. So individuals with unique ethnic combinations can be trivial to identify by their genetic data. Now consider that genetic data can also be used to predict traits such as height, hair color, eye color, etc [0]. Reliable triangulation is already possible, and becomes increasingly more accurate as more data becomes available. 0: E.g.this company- https://snapshot.parabon-nanolabs.com/ https://snapshot.parabon-nanolabs.com/

gwern 8y ago

Very roughly, ~2%: https://www.biorxiv.org/content/early/2018/06/19/350231 https://www.biorxiv.org/content/early/2018/06/19/350231

dangrossman 8y ago

That's how a local cold murder case was solved. DNA from a 25-year-old crime scene was run against a genealogy database, and found a familial match. Police set up a sting to obtain DNA from that person's relatives. They found a DNA match with the brother's water bottle taken from the trash. The brother had never submitted a DNA sample to any databases himself. https://lancasteronline.com/news/local/christy-mirack-s-slaying-solved-with-arrest-of-lancaster-county/article_f05a2ee4-78b2-11e8-ad10-4382ef42f96d.html https://lancasteronline.com/news/local/christy-mirack-s-slay... The alleged killer was the DJ at my wedding. The trial's in May.