The Genoscope (in Evry) and the CNRS alpine ecology laboratory (in Grenoble) worked together to develop a novel method that reconstructs the history of flora from free DNA collected in sediment. This technique was employed in the Arctic, where 242 cores were made, particularly in sediments dating back to the last ice age [1].

“Thanks to the amplification and sequencing of extracted DNA, we were able to reconstruct the history of flora in the last 50,000 years”, says Patrick Wincker. “In parallel, intestinal samples of mammoths and woolly rhinoceroses preserved in ice helped to determine their diet.” The researchers thus demonstrated a great diversity of flora during the last glacial period, with a predominance of non-grassy plants, contrary to what was accepted by the scientific community. Analysis of the intestines of large herbivores corroborates this result. “At the peak of glaciation 20,000 years ago, this diversity sharply declined”, continues the biologist. “It turns out that 10,000 years later, the Arctic tundra was transformed and dominated by woody plants and grasses.” These results suggest that mammoths and woolly rhinoceroses had many difficulties adapting to the new diet that was forced upon them, which possibly contributed to their extinction.

[1] 120,000 to 10,000 years BCE.