GENETICS × HUMAN EVOLUTION

Reading the Dead

1984 to 2010 CE

Phanerozoic · Cenozoic · Quaternary · Holocene · Meghalayan

DNA survives in bones and skins for tens of thousands of years, but it comes out broken into short pieces and chemically scarred in a particular way at the ends. For a while that damage made the field unreliable, since a stray modern strand looks better than a genuine ancient one. Then the damage itself became the test: a sequence without it is a contaminant. A Neanderthal genome followed in 2010.

Why it matters

Extinct species stopped being silent. Nearly all that is known here about Neanderthals and Denisovans, and much of the Black Death and the first dogs, was read out of their own DNA rather than inferred from their bones.

Dating & uncertainty

The first sequences from an extinct animal came in 1984, from a museum skin. They were short and easily contaminated; the field became reliable only once damage patterns in old DNA were understood and used as a test of authenticity.

Sources

1. Higuchi et al. (1984), Nature · DNA sequences from the quagga, an extinct member of the horse family
2. Green et al. (2010), Science · A draft sequence of the Neandertal genome
3. Dabney, Meyer & Pääbo (2013), Cold Spring Harbor Perspectives in Biology · Ancient DNA damage

Earth history as one day

23:59:59.9992799 µs before midnight

if Earth’s 4.54 billion years were compressed into a single day