I am these days trying to update my already obsolete map series on European and Mediterranean ancient mtDNA, as I did in the past I'm using Jean Manco's site as reference.
However many clades seem poorly described (maybe because the haplogroup knowledge has varied since the papers were published) and I'm taking my time trying to identify the confusing haplogroups when possible.
One of the strangest cases is the two individuals from Sunghir, in Central Russia, from Gravettian times (25,000 BP). Their well preserved mtDNA has only one mutation from the Cambridge Reference Sequence (CRS), which is H2a2a, in the HVS-1 (source).
While the "raw CRS" in the HVS-1 region is relatively common (specially within mtDNA H but occasionally in U* and R0 and HV as well), haplogroups with the 16129A mutation (and only that one) are not.
In fact, after studying the matter with the help of PhyloTree, I realized that only one modern haplogroup carries that mutation: H17'27 (expanded from an original H17 finding by Roostalu in 2007, now known as H17a). I've been searching for further information and there is not much but at least the haplogroup was detected at a frequency of 0.5% in a pooled sample of Central Europe, the Balkans and Dubai by A. Brandstätter in 2008.
Another finding was to realize that someone else had noticed this fact before I did: someone by the name of Maciamo posted his surprise at that same finding (he calls it pre-H17 but it's the same thing) at the forum of Eupedia almost a year ago.
So are we before the oldest known mtDNA H ever and finally the evidence supporting my theory that this haplogroup spread at the colonization of Europe, as the huge star-like structure it has (only comparable to that of M, produced at the beginning of the Eurasian colonization)? I believe so.
Notice that it is not mtDNA H-root, which would produce an imprecise "CRS" sequence, but already a derived lineage, indicating that the spread of mtDNA H happened before this date of 25,000 years ago, that is at least as early as the Gravettian expansion.