Inbreeding didn’t kill woolly mammoths 4,000 years ago – something else did
Around 4,000 years ago, the woolly mammoth ceased to exist and scientists have blamed generations of inbreeding for their demise.
However, we now know that it wasn’t incest that killed them.
But we don’t know what did.
A new study conducted by the University of Stockholm has revealed it was probably a freak event such a plague or an extreme storm which wiped out the mammoths, rather than rampant inbreeding.
The theory comes after scientists discovered a handful of mammoths became stranded on an island in the Russian Arctic around 10,000 years ago, swelling theirnumber by hundreds despite an extremely limited gene pool.
But when the researchers conducted a genetic analysis of specimens found on Wrangel Island, they debunked the idea that harmful genetic mutations caused by inbreeding led to a ‘genomic meltdown’.
The specimens consisted of of 13 mammoths from the island and seven earlier specimens from the mainland, together representing a span of 50,000 years.
The research suggests that although the mammoths did have low genetic diversity, the population was stable enough to occupy the land for thousands of years before they all disappeared.
Professor Love Dalén, who led the study, said the population was successfully purging the major genetic mutations, but minor ones were accumulating.
‘We can now confidently reject the idea that the population was simply too small and that they were doomed to go extinct for genetic reasons,’ he said.
‘This means it was probably just some random event that killed them off, and if that random event hadn’t happened, then we would still have mammoths today.’
The findings, which were published in the journal Cell, reveal the woolly mammoths went through a severe ‘bottleneck’ after once roaming around Europe, Asia and the northern reaches of North America.
Mammoth facts
- Most mammoth populations died out around 10,000 years ago but some survived on Wrangel Island in the Arctic until as recently as 1650 BC
- They were around 13 feet tall (four metres) and weighed around 6 tonnes.
- Some of the hairs on woolly mammoths could reach up to 3 feet (1 m) long, and their tusks were around 2.5 metres long
The beasts dwindled in numbers as climate change and human hunters posed an increasing threat and made them retreat north.
But when Wrangel island in the Arctic was surrounded with water due to rising sea levels, the population was cut off.
‘Mammoths are an excellent system for understanding the ongoing biodiversity crisis and what happens from a genetic point of view when a species goes through a population bottleneck because they mirror the fate of a lot of present-day populations,’ said Dr Marianne Dehasque, of Uppsala University, the first author of the paper.
But as Colossal Biosciences want to de-extinct the mammoth in just four years, maybe we’ll have a lot more to learn.