Abstract: Permafrost-preserved teeth, up to 1.65 million years old, identify a new kind of mammoth in Siberia. The million-year-old genome is here. Mammoth teeth preserved in eastern Siberian permafrost have produced

the oldest ancient DNA on record, pushing the technology close to, but perhaps not past, its limits. Genomic DNA extracted from a trio of tooth specimens excavated in the 1970s has identified a new kind of mammoth that gave rise to a later North American species.

Researchers had suspected that ancient DNA could survive beyond one million years, if the right sample could be found. Once an organism dies, its chromosomes shatter into pieces that get shorter over time. Eventually, the DNA strands become so small that — even if they can be extracted — they lose their information content. Orlando’s team found that fragments as short as 25 DNA letters in their horse bone, from the Canadian Yukon Territory, could still

be interpreted.