Ancient DNA can reveal all sorts of things about the past – from the mysteries of human evolution to the secrets of Earth’s prehistoric climate. We’ve found some pretty old examples of it – but what is the oldest DNA ever recovered?

What is ancient DNA?

DNA is the hereditary material in humans and almost all other organisms that carries genetic information for the development, functioning, growth, and reproduction of that organism. Ancient DNA (aDNA) is DNA isolated from ancient sources.

Molecules of DNA are fairly fragile and degrade over time, which means that finding really old examples is incredibly rare – but not impossible…

Oldest DNA ever discovered

The world’s oldest DNA was discovered in 2022 – and it’s an astonishing 2 million years old.

Unearthed in Ice Age sediment in northern Greenland, the genetic material had been locked in permafrost since the Pliocene. Once sequenced, the DNA opened up a window into the past, shedding light on the array of animals and plants that once inhabited the area.

These included reindeer, geese, hares, rodents, crabs, and mastodon, as well as poplar, birch, and thuja trees, and a variety of Arctic and boreal shrubs and herbs.

Prior to this discovery, the oldest DNA ever recovered came from 1.2-million-year-old mammoth teeth unearthed in Siberian permafrost. It marked the first time that DNA exceeding 1 million years old had been retrieved from an ancient organism. 

Although only around half as old as the Greenland samples, this DNA was recovered directly from biological material, making it the oldest to be sequenced from physical specimens.

Another noteworthy example of some really old DNA hailed from a horse found preserved in Canadian permafrost in 2013, which was dated to between 780,000 and 560,000 years old. It held the record for oldest DNA until it was bested by the mammoth molar.

What is the oldest human DNA?

But enough about ancient animals – what about human DNA?

Things get a little trickier when it comes to ancient humans. Our ancestors first evolved in Africa, where it gets pretty hot – and, as you may have noticed, all of the examples mentioned above are from much colder climes.

DNA degrades quicker in warmer climates, so finding ancient examples of it that are not in permafrost is no mean feat. That said, it has been done.

The oldest hominin DNA on record comes from a 430,000-year-old genome, which was found in a cave in Spain. Known as “Sima de los Huesos” (“Pit of Bones”), the underground pit housed the remains of 28 hominins who were early members of the Neanderthal lineage.

If we look beyond DNA, to other forms of genetic data, we can find some even older examples. Last year, researchers discovered the oldest human genetic data yet in 2-million-year-old hominid fossils in South Africa. Protein sequences extracted from the teeth of the primate Paranthropus robustus are by far the oldest genetic information ever recovered from any hominid. 

The oldest-ever proteins, meanwhile, were obtained from ostrich eggshells in Tanzania back in 2016. They are up to 3.8 million years old.