"DNA from cave dirt tells tale of how some Neanderthals disappeared"

Estatuas cave in northern Spain was a hive of activity 105,000 years ago. Artifacts show its Neanderthal inhabitants hafted stone tools, butchered red deer, and may have made fires. They also shed, bled, and excreted subtler clues onto the cave floor: their own DNA. “You can imagine them sitting in the cave making tools, butchering animals. Maybe they cut themselves or their babies pooped,” says population geneticist Benjamin Vernot, a postdoc at the Max Planck Institute for Evolutionary Anthropology (MPI-EVA), whose perspective may have been colored by his own baby’s cries during a Zoom call. “All that DNA accumulates in the dirt floors.”

(...) At the same time, the more plentiful mtDNA from Estatuas cave shows declining diversity. Neanderthals in the cave 113,000 years ago had at least three types of mtDNA. But the cave’s Neanderthals 80,000 and 107,000 years ago had only one type. Existing ancient DNA from Neanderthal bones and teeth had also pointed to a falloff in genetic diversity over the same period.

Arsuaga suggests Neanderthals thrived and diversified during the warm, moist interglacial period that started 130,000 years ago. But about 110,000 years ago, temperatures in Europe dipped suddenly as a new glacial period set in. Soon after, all but one lineage of Neanderthals disappeared. Members of the surviving lineage repopulated Europe during later, relatively warm spells, with some taking shelter in Estatuas cave.

Those survivors and their descendants include what Arsuaga calls the “famous” classic Neanderthals, such as skulls from Vindija and La Ferrassie in France. He notes they had bigger brains—up to 1750 cubic centimeters (cm3)—than earlier Neanderthals, whose cranial capacities were no larger than 1400 cm3. Arsuaga says this mirrors a similar pattern in modern humans in Africa, who also underwent a surge in brain size and multiple population replacements with the onset of the ice age.

Trouvé ici.