Just as Vikings pillaged their way from Norway to Greenland and Iceland 1000 years ago, another group of furry raiders appears to have made a similar trek: common house mice. A new analysis of ancient and modern mouse DNA suggests that the mice in Iceland and Greenland came from Norway.
Scientists began by looking at mitochondrial DNA (mtDNA) extracted from living mice in Iceland and Greenland as well as from mouse bones found in old settlements. The ancient gene sequences were strikingly similar to those of modern mice found in UK and Norway, as well as to modern Icelandic mice, suggesting a common origin in either the UK or Norway. The low genetic diversity in Iceland, to boot, suggests recent colonization by a small number of stowaway mice. These findings have prompted speculation that mice may have arrived in the islands in Viking ships, though there is no evidence that that’s the case.
As scientists continue using human DNA to map our ancestors’ migrations, it’s neat to be reminded that there might be similar patterns of migration in species that tend to live with humans. Perhaps the bones of mice may in the future provide helpful clues for figuring out where ancient humans went and what they brought with them.
[via New Scientist]
What’s the News: Climate change may have sparked the demise of early Viking settlements in Greenland, according to a new study published online in the Proceedings of the National Academy of Sciences, when temperatures cooled rapidly over several decades. Around the time the Vikings disappear from the island’s archaeological record, temperature appears to have plunged. Nor were the Vikings the only people in Greenland whose fortunes rose and fell with the average temperature, the study suggests. Earlier cold spells may have played a role in the collapse of two previous groups on the island.
When the Vikings set sail for the British Isles they had small, furry stowaways aboard their ships, and researchers say that the descendants of those mice can offer clues about the voyages taken by Viking seafarers. A new study examined the DNA of house mice throughout the British Isles and found that mice from areas where the Vikings are thought to have settled are genetically distinct from mice in other regions.
Says study coauthor Cath Jones: “We have found that most of the mice in the north of Scotland – from Orkney, Shetland and Caithness – are all of one very similar type that we have named the Orkney lineage and they are very similar to Norwegian mice. And the only explanation for that is that when the Vikings came raping and pillaging to Scotland they took their house mice with them” [Scotsman].