science.sciencemag.org/lookup/doi/10.1126/science.aam9695[/PLAIN] [Broken] Researchers have found a way to extract DNA from cave floor sediment strata. Mixed in with a lot of other mammalian DNA is DNA from Neandertal and Denisovan people who inhabited the caves many thousands of years ago. The DNA samples are often mitochrondrial DNA, which is used to determine relationships among samples from other groups. If you recall the news stories and academic papers about a human mitochondrial Eve, this is along the same lines. @BillTre posted a link yesterday about a family tree for domesticated dogs based on analyzing similarities for samples of nuclear DNA. This is somewhat different, it is a distinct, specialized subset of DNA. http://www.cell.com/cell-reports/fulltext/S2211-1247(17)30456-4 It involved a large number of samples from 161 breeds of dog. This study on sediment DNA has very few samples so far. It has some potential to be a major advance in enumerating the human family tree more clearly. The major plus is that no skeletal remains are required. So, archeological sites with tool and charcoal pits but no skeletal remains may be able to provide some genetic information.