Haplogroup K is a genetic lineage in humans that is traced via mutations in the DNA that originated thousands of years ago in western Asia. The mutations used to trace haplogroup K are inherited only through the parent that gave birth, allowing geneticists to trace maternal ancestry in populations.
Haplogroup K is traced by looking at mitochondrial DNA. Mitochondria are tiny organs of the cell that replicate themselves independently of the nucleus. They have their own DNA and are inherited directly from the egg cell of the parent at fertilization. Mitochondria containing the mutations characteristic of haplogroup K are particularly common in people of Middle Eastern descent, such as Kurds, Palestinian Arabs and Yiddish-speaking Jews (called Ashkenazim). The haplogroup is prevalent in European populations as well but in lower percentages of the population than in Middle Eastern groups.