A recent study published in PNAS reported that mice had been cloned from frozen DNA (journal abstract here; press report here). This had been thought impossible: that cellular ice crystals would destroy the DNA.
This does not constitute a universal panacea for recovering extinct species, but it has implications for DNA recovered from unfossilised remains recovered from permanently frozen locations, especially Antarctica, Canada, and Russia.
There would remain a number of scientific hurdles, including incubation, but the puzzle pieces are starting to fall into place. Yet there are a couple of ominous tones in this news.
First, we may be running out of time. Permafrost regions have begun thawing already. (And this is a double-edged sword: on the one hand, it will make scientific discovery easier for a period of time, but on the other hand, it will likely hasten the warming process as masses of organic matter will also thaw, rot, and release more atmospheric carbon to hasten the warming process.)
Second, it would be tragic if scientific progress bred complacency towards looming extinctions. Prevention - preserving whole ecosystems - would be so much easier and less fraught than attempting to recreate the systems. But our form of democracy is traditionally geared to the dissonance of desiring an outcome but not making the hard decisions. A recipe for complacency.