What is the evolutionary significance of unique fingerprints

[md2000]

@Some_Call_Me.Tim

It’s much easier for prosecutors to obtain convictions if everyone is convinced that they are unique. Humans don’t handle very low probability scenarios like matching fingerprints well, so many people assume uniqueness, even when there’s evidence to the contrary.

Brandon Mayfield

Your FBI tax dollars at work.

Following the 2004 Madrid train bombings fingerprints on a bag containing detonating devices were found by Spanish authorities. The Spanish National Police shared the fingerprints with the FBI through Interpol. 20 possible matches for one of the fingerprints were found in the FBI database and one of the possible matches was Brandon Mayfield. His prints were in the FBI database because of his arrest two decades earlier.[clarification needed] He became the prime suspect because of his conversion to Islam and because he had represented one of the Portland Seven.[1]

Or, as Paul Simon said:
There’s no doubt about it,
It’s the myth of fingerprints.
I’ve seen them all and they are all the same.

[md2000]

Another indicative point - we have palm and foot patterns too. This suggests that either the programming for fingerprints controls those areas also (and so it is an accident) or more likely perhaps, it was a development earlier in evolution when both upper hands and lower hands (toes) were used for gripping.

[dracoi]

@Francis_Vaughan

If we had identical ones there would need to be genetic coding for the identical prints, rather than a generic formula that generates fingerprints with no direction other than that they be fingerprint like. Those genes would need to be conserved, which takes a lot of work (where work is a rather abstract thing here, but it isn’t trivial.)

Depending on how identical you want it, the genetic coding might not be very cumbersome. It’s already basically telling the skin to form ridges a certain distance from other ridges. If you introduced a “seed” for those ridges to start from, the outcome might be very close to identical without lots of additional coding.

[Francis_Vaughan]

You would also need a mechanism that uses that seed in a manner that produced identical output. That would need coding for, and conserving. (This becomes the Kolmogorov Complexity - you don’t really win, just move the bits around.) What is more important is that in order to remain identical the DNA coding the seed would have to be conserved across the species. The lack of any evolutionary pressure to conserve it (since so far as we know, there is no advantage in having identical fingerprints) would mean it would be very very unlikely to be conserved.

The bottom line is that if we had identical fingerprints we would want to know why - as there would have to be significant and unusual forces at work to keep them that way.

[Kobal2]

@ftg

But they’re still arguing over why zebras have stripes at all, never mind why they vary.

Gives predators a raging headache when they’re running after 'em.

[Francis_Vaughan]

@Kobal2

Gives predators a raging headache when they’re running after 'em.

It struck me that zebra stripes are not all that different to the “dazzle” stripes used in WW1 for ships - where the intent was to make distance and boundary estimates difficult.

It may be that a predator chasing a herd of zebra will find it much harder to visually isolate and estimate distance to individual animals, and overall have a generally harder time in the chase.

[dracoi]

@Francis_Vaughan

You would also need a mechanism that uses that seed in a manner that produced identical output. That would need coding for, and conserving. (This becomes the Kolmogorov Complexity - you don’t really win, just move the bits around.) What is more important is that in order to remain identical the DNA coding the seed would have to be conserved across the species. The lack of any evolutionary pressure to conserve it (since so far as we know, there is no advantage in having identical fingerprints) would mean it would be very very unlikely to be conserved.

The bottom line is that if we had identical fingerprints we would want to know why - as there would have to be significant and unusual forces at work to keep them that way.

I agree that there’s no selective pressure to keep fingerprints identical and that it wouldn’t last in the wild. I’m just saying that achieving identical patterns doesn’t necessarily require a lot of complicated genetic overhead. If there was a selective advantage to particular fingerprint patterns, it could probably be achieved by adding/tweaking just a couple of genes.