The oldest intact human mummy, Ötzi the Iceman, comes from a genetic line that has either died off or become extremely rare, according to a new DNA study.

The 5,200-year-old Ötzi was discovered frozen in a glacier along the border between Austria and Italy in 1991.

New analysis of a mere 0.002 ounces (70 milligrams) of this intestinal material has allowed scientists for the first time to sequence Ötzi's complete mitochondrial DNA.

Mitochondrial DNA is passed from mothers to their offspring, and although it can accumulate mutations, part of it usually remains unchanged, making it useful for tracing lineage through mothers.

Mutations in Ötzi's mitochondrial DNA formed "a unique subcluster within a known European lineage," said lead author Franco Rollo of the University of Camerino in Italy.

However, the Iceman's line became, "if not extinguished, extremely rare" during the last 5,000 years, Rollo said.

The research was published online today in the journal Current Biology.

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