While the emphasis of this news item is that mammoths seem to have survived in some areas further than the fossil record suggests, up to at least 10,500 years ago, the true interest of this research for me is that they seem to have developed a novel technique to find ancient DNA in sediments, potentially freeing science from having to rely only on fossils for that purpose. Also the method allows for accurate archaeological datation of such DNA remains.
This is potentially revolutionary in the field of historical genetics (and others):
Dirt DNA has lots of exciting potential to contribute to extinction debates in other parts of the world too, as well as a range of archaeological questions," said Willerslev, who also points out that the approach is not restricted to looking back at the past. "We can also use it to make a list of modern species living in any particular location," he said.
Source: Science Daily. While the research is said to be published at PNAS, I can't find it - so I guess it's not still in print.