My wife is W1, with a maternal line that traces back to the British Isles. 23 and me is now on the page that mt-DNA haplogroup W has an Indo-European origin now. Here is the snippet from her ancestry report:
"The name of the Corded Ware culture comes from their characteristic pottery, which was decorated with cord-like designs. The people of the Corded Ware culture likely grew out of the steppe culture north of the Caspian Sea approximately 4,900 years ago, and were highly mobile and used horses and wagons extensively. They spread west to cover much of central and eastern Europe from the Volga to Germany and the coast of the Baltic Sea, spreading proto-Indo-European language with them. In fact, their language was the common prehistoric ancestor of Celtic, German, Baltic and Slavic languages.While the expansions of horseback warriors from the steppes are associated most strongly with the spread of paternal lineages, a number of maternal lineages also grew in frequency with the spread of the Corded Ware culture from the east. Researchers have found members of haplogroup W in remains from both the steppes and Corded Ware sites, suggesting that W may have been one of these maternal lineages."