The first largescale study of ancient DNA from early American people has confirmed the devastating impact of European colonisation on the Indigenous American populations of the time.
Led by the University of Adelaide's Australian Centre for Ancient DNA (ACAD), the researchers have reconstructed a genetic history of Indigenous American populations by looking directly into the DNA of 92 pre-Columbian mummies and skeletons, between 500 and 8600 years old.
Published today in Science Advances, the study reveals a striking absence of the pre-Columbian genetic lineages in modern Indigenous Americans; showing extinction of these lineages with the arrival of the Spaniards.
"Surprisingly, none of the genetic lineages we found in almost 100 ancient humans were present, or showed evidence of descendants, in today's Indigenous populations," says joint lead author Dr Bastien Llamas, Senior Research Associate with ACAD. "This separation appears to have been established as early as 9000 years ago and was completely unexpected, so we examined many demographic scenarios to try and explain the pattern."
"The only scenario that fit our observations was that shortly after the initial colonisation, populations were established that subsequently stayed geographically isolated from one another, and that a major portion of these populations later became extinct following European contact. This closely matches the historical reports of a major demographic collapse immediately after the Spaniards arrived in the late 1400s."