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A new study, led by geologist and glacier expert Kurt Kjær, has discovered ancient environmental DNA (eDNA) that describes the rich plant and animal presence in the Kap København Formation in Peary Land of northern Greenland – now a polar desert. This DNA dates back to an astounding two million years ago.
The DNA record shows a high-latitude forest ecosystem with mixed vegetation of trees including poplar, birch, and thuja, and a variety of Arctic boreal shrubs and herbs too, many of which had not previously been detected at the site from macrofossil and pollen records.
The new discovery confirms presence of mitochondrial DNA from animals including mastodons (now extinct), reindeer, rodents and geese. All of these are ancestral to their present-day relatives.
Paleoclimatic records show mean annual temperatures of 11–19 °C above present-day values in the area. The presence of marine species including horseshoe crab and green algae supports a warmer climate than today.
According to the study, such ancient eDNA possibly survives by binding itself to mineral surfaces.
Out of the 102 genera detected in the ancient eDNA of Kap København, 39% no longer grow in Greenland, but are found in the north American boreal and northern deciduous and maritime forests. Many plant genera identified in the eDNA assemblage require higher temperatures than those at any latitude on Greenland today.
The metazoan mitochondrial and nuclear DNA record was much less diverse than that of the plants. However, one extinct family, one that is not found in Greenland anymore, and four vertebrate genera native to Greenland were identified.
In an unexpected discovery, a single reef-building coral (Merulinidae) and several arthropods, with matches to two insects – Formicidae (ants) and Pulicidae (fleas) – and one marine family – Limulidae (horseshoe crabs) – were also identified in the DNA record.
No single modern plant community or habitat includes the range of populations represented in many of the macrofossil and DNA samples from Kap København, the study noted.
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