Scientists who sequenced the mitochondrial DNA of a 38,000-year-old Neanderthal returned no evidence of ancestral interbreeding with our long-lost cousins.

That mild disappointment aside, the study, published today in Cell, is an impressive technical achievement.

“For the first time, we’ve built a sequence from ancient DNA that is essentially without error,” said study co-author Richard Green, a Max-Planck Institute anthropologist, in a press release.

They could do so in part because the mitochondrial genome, housed in cell-powering mitochondria rather than cell nuclei, contains just 37 genes. (The full human genome contains about 25,000 genes.) The researchers sequenced their sample no fewer than 37 times.

Because mitochondrial DNA is passed directly from mother to child without mixing with a father’s genetic material, it gives evolutionary anthropologists a well-marked trail into the past.

Scientists eventually hope to sequence a full Neanderthal genome.

From: Wired