Origin: A Genetic History of the Americas

Some of populations and population movements during the Upper
Paleolithic learned from genetic and archaeological evidence.
Between 50,000 and 34,000 years ago, a period that archaeologists call
the Upper Paleolithic, humans who looked like us had left Africa and were
rapidly migrating across the globe, from Western Europe to Australia. As
they encountered new environments, already inhabited by other kinds of
humans we call archaic—Neanderthals and Denisovans—the so-called
anatomically modern Homo sapiens found ways to adapt to each new place.
They developed remarkable technological solutions to the problems of
finding food, shelter, and transportation. They made sophisticated stone
tools, including points, blades, and hide scrapers. They also made tools out
of bone, including sewing needles, awls, and points. They developed new
forms of expressive art: cave paintings, beautifully carved figurines,
jewelry. They interacted with their archaic cousins everywhere they went.
Some of these interactions led to children, traces of whose ancestry can be
found to various degrees in the genomes of all populations of humans today
(see the “Genetic Legacies from Archaic Humans” sidebar). About 45,000
years ago, the genome of an individual from the Ust’-Ishim site in western
Siberia who belonged to a population ancestral to Europeans and East
Asians shows evidence of Neanderthal ancestry dating to perhaps as early
as 60,000 years ago.