观点科学

New revelations about humans’ near extinction spark scepticism

The further back in time we go, the more slippery scientific deductions about the origins of Homo sapiens become

The writer is a science commentatorDespite being the dominant species on the planet, we Homo sapiens should count ourselves lucky to exist at all. Our ancestors were on the brink of extinction around 900,000 years ago, according to scientists, with little more than a thousand breeding individuals eking out a lonely existence for more than 100,000 years.

This supposed “super bottleneck” in our evolutionary history, sketched out using a complex mix of genetic analysis and computer modelling, might explain gaps in the fossil record (minimal population would leave minimal remains). It also roughly coincides with a period of climate change that could have decimated the survival chances of our predecessors. A population crash would have promoted inbreeding — which might additionally explain why humans show relatively low genetic diversity compared with other mammals.

But the finding has met with some scepticism, highlighting the challenge of reconstructing the story of our own species. The further back in time academics try to reach, the more slippery their deductions become. In the absence of well-preserved DNA from ancient humans, it is entirely possible that our real origin story will never be told.

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