Here is the full information given at 23andme (where also appears the Basque reference). Copy paste:
Introduction K branched off
haplogroup U8 about 35,000 years ago. It continues to have a strong presence in the region today, reaching levels of 20% among Druze Muslims and about 10% among Kurds, Palestinians and Yemenites. It is also found among the Gurage of Ethiopia, who are thought to be descended from Arabian invaders.
K spread from the Near East into Europe about 15,000 to 12,000 years ago, as the Ice Age was ending and temperate forests spread over the previously frigid continent. It is still found at low levels in most European populations, where many branches of the haplogroup match identical ones from the Near East. That close similarity suggests that more recent migrations also may have carried haplogroup K from the Near East to Europe, perhaps in conjunction with the spread of agriculture about 8,000 years ago.
Haplogroup K also extends into Central Asia as far as the Altay Mountains, a range that runs along the western edge of Mongolia's Gobi Desert. It may have reached there with relatively ancient migrants from the Near East, and then been spread to other parts of Asia during the medieval expansion of the Turkic peoples to the Urals and modern-day Turkey.
Altogether there are dozens of unique branches within this haplogroup, including some of unknown distribution. However, a few populations carry branches of haplogroup K that have been extensively characterized.
The Ancient Basques Geneticists have taken a great interest in the Basques of far northern Spain because of their unusual language, which suggests they descend from some of the original settlers who arrived in southwestern Europe during and after the Ice Age. Though
haplogroup K is relatively rare among the Basques today,
mitochondrial DNA extracted from prehistoric burials suggests it was much more common in the past. In remains excavated from three cemeteries dating to between 4,000 and 5,000 years ago, haplogroup K showed up at levels of 17 to 24%. A similar sample from a medieval Basque cemetery found that by around 1,500 years ago the haplogroup's levels had fallen to its present-day level of about 4%.
What could account for this near-disappearance of haplogroup K among the Basque? It could be that female migrants to the region married into the Basque population, swamping out the K lineages with their own haplogroups. Or it could be that the Basque population experienced a crash at some time in the past that disproportionately eliminated haplogroup K from the gene pool.
K in the Ashkenazi A few branches of
haplogroup K, such as K1a9, K2a2a, and K1a1b1a, are specific to Jewish populations and especially to Ashkenazi Jews, whose roots lie in central and eastern Europe. These branches of haplogroup K are found at levels of 30% among Ashkenazi. But they are also found at lower levels in Jewish populations from the Near East and Africa, and among Sephardic Jews who trace their roots to medieval Spain. That indicates an origin of those K haplogroup branches in the Near East before 70 AD, when the Roman destruction of Jerusalem scattered the Jewish people around the Mediterranean and beyond.
About 1.7 million Ashkenazi living today – about 20% of the population – share a single branch of the K haplogroup, K1a1b1a. The diversity of that haplogroup among Ashkenazi suggests that it arose in the Near East between 2,000 and 3,000 years ago, and that everyone who shares it today could have shared a common ancestor as recently as 700 years ago. A similar pattern in two other K branches that are common among the Ashkenazi, K1a9 and K2a2, as well as the N1b branch of haplogroup N, has led researchers to conclude that 40% of the Ashkenazi living today – about 3.4 million people – could descend from as few as four women who lived within the last 2,000 years.
Historical information supports that conclusion. The Ashkenazi tradition traces back to a small number of people who migrated from northern Italy to the Rhine Valley of Germany around 700 AD, then grew over the next 1,300 years to a population of more than 5 million.
Ötzi the Ice Man Ötzi the Ice Man was discovered in 1991, protruding from a snow-bank high in the Alps near the Austrian-Italian border. His 5,300-year-old remains turned out to be so well preserved that researchers were able to construct a detailed account of his life and death. They have also determined that his maternal line was derived from
haplogroup K, which remains common in Alpine populations today.
Chemical analysis of Ötzi's teeth indicates he came from the Italian side of the Alps. He had suffered during the year before his death with whipworm, a stomach parasite that was found in his digestive tract. Yet he was fit enough to climb 6,500 feet in elevation during the day or two before he met his end in a rocky alpine hollow – pollen grains mixed in with the food in his colon, which included red deer and Alpine ibex meat as well as wheat and barley, show that his last few meals were consumed at a much lower elevation than the site where he died, and that they were eaten during the spring.
Ötzi apparently was murdered, struck by a stone arrow point that was found lodged in his left shoulder. The twisted position of his body indicates that the murderer, or one of his accomplices, pulled the arrow's shaft out of Ötzi's prone body – perhaps to remove evidence of the killer's identity from the scene of the crime. Yet whoever killed Ötzi did not take the valuable and finely wrought copper axe that he carried with him – an indicator that at the age of 45, the Ice Man may have been a figure of some importance in his community.
Recently, scientists who were able to extract
mitochondrial DNA from Ötzi's remains discovered that it belonged to haplogroup K, which reaches levels of 20 to 30% in present-day local populations. But Ötzi's mitochondrial DNA, which fell into the K1 family of haplogroup K, did not match any of the branches that are known today. His maternal line must have died out in the 5,300 years since Ötzi's death.
Ötzi's paternal line may very well have died out as well – his mitochondrial DNA contains two mutations that are associated with low sperm motility, so he could have been infertile. We can imagine that at the age of 45, with a prominent position in his community but no heirs to support him, Ötzi might have found himself high in the Alps on a chilly spring day 5,300 years ago desperately fleeing his enemies.