[wildbill]

Did you read the article? Sounds like reverse evolution to me.

[SunkenCiv]

It's not too farfetched to take the "tribal myth" version of their origin, but it's also not too farfetched to believe that they've been around for a very long time.

all of the Mlabri mitochondrial DNA turned out to be identical

An isolated population (island, or culturally insular) will through luck of the draw eventually wind up with a single surviving pool of genes here and there. Were that not true, there wouldn't be recognizable ethnic groups (most of which are of course larger than this); analogously, populations physically isolated on islands (such as the Bounty descendants on Pitcairn Island) wind up with a pretty narrow genome, and/or a single last name. :') Thanks wb.