At Ancestry.com we are provided with an updated distribution map for mtDNA haplogroup U5 (see above) and informed that
Haplogroup U5 was the most common maternal lineage among European hunter-gatherers, not just during the Palaeolithic and Mesolithic, but until much later in North and Northeast Europe, notably with the Sami people. U5 is absent from Southwest Asia and very low in most of the Middle East, where its presence could be attributed to foreign invasions and settlements from the Bronze Age onwards (Hittites, Indo-Iranians, Phrygians, Armenians, Greeks, etc.).
U5 correlates mostly with Y-DNA haplogroups I, N1c1 and R1a.
On another Ancestry.com page and at Family Tree DNA, we are informed more about the ethnicity correlates of these Y-DNA haplogroups:
Hg I is Anglo-Saxon/Danish.
Hg N1c1 is Baltic with 5 subclades as follows:
1) North European Subclade (Z1936+,Z1935+)
2) North-Baltic Subclade (VL29+,L1022+)
3) South-Baltic Subclade (L550+,L1025+)
4) Scandinavian II (L550+,L1025-)
5) Ugric Subclade (Z1936+,L1034+)
Hg R1a is Norse Viking.
Celtic Y-DNA tends to be R1b.
Just ordered the Y-DNA test for my dad - can't wait to see the results!