Haplogroup K is a human mitochondrial DNA (mtDNA) haplogroup.
Haplogroup K is actually a part of the larger haplogroup U. It is a mostly Eurasian haplotype, and is believed to have first appeared when human populations expanded through Europe after the last glacial maximum in 16,000 BC.
The mitochondrial super-haplogroup U encompasses haplogroups U1-U7 and haplogroup K. Haplogroup K is found through Europe, and contains multiple closely related lineages indicating a recent population expansion. The origin of haplogroup K dates to approximately 16,000 years ago, and it has been suggested that individuals with this haplogroup took part in the pre-Neolithic expansion following the Last Glacial Maximum.
Analysis of the mtDNA of Utzi the Iceman, the frozen mummy from 3300 BC found on the Austrian-Italian border, has shown that Otzi belongs to the K1 subcluster of the mitochondrial haplogroup K, but that it cannot be categorized into any of the three modern branches of that subcluster.
Approximately 32% of the haplotypes of modern people with Ashkenazi Jewish ancestry are in haplogroup K.