UPPSALA, Sweden — Filipinos are descended from an ancient species of human beings who lived during the last Ice Age, a new study finds.
Researchers from Uppsala University in Sweden say Denisovans – or Denisova hominins – are an extinct subspecies who interbred with Neanderthals and Homo sapiens. The study reveals that the indigenous occupants of the Southeast Asian archipelago have the most Denisovan DNA in the world. Regarded as the aboriginal inhabitants, there are an estimated 15,000 Philippine Negritos. They live on several major islands including Luzon, Palawan, Panay, Negros, Cebu, and Mindanao.
“Although, much later, Negritos admixed with the East Asian group that had a small proportion of Denisova DNA, we found that the Negritos had a proportion markedly higher than those of other ethnic groups. Compared with Australians and Papuans, the Negritos’ Denisovan ancestry was up to 46 per cent higher,” says lead author Dr. Maximilian Larena in a university release.
In particular, a tribe of nomadic forest dwellers called the Ayta Magbukun have the most of this prehistoric DNA.
“This admixture resulted in varied levels of Denisovan genes in the genomes of Filipino Negritos and other groups. On Southeast Asian islands, Negritos later admixed with people who arrived from East Asia and had some Denisovan genes, which caused dilution in the share of Denisovan DNA. But some groups, such as Ayta Magbukon, interbred only a little with the people who later migrated to the islands,” adds Professor Mattias Jakobsson.
“That’s the reason why the Ayta Magbukon retained most of their Denisovan genes and therefore have the highest levels of those genes in the world.”
Unearthing more early humans
The existence of the mysterious Denisovans was only discovered just over a decade ago. Researchers believe they lived in Asia before the global expansion of modern humans tens of thousands of years ago. Several hominin species were alive at the same time, a scenario that has been likened to Lord of the Rings. Scientists believe some of these early humans have yet to be discovered.
Two years ago, a previously unknown hominin named Homo luzonensis was discovered in the Philippines. The diminutive creature lived at least 50,000 years ago and made headlines around the world. The Denisovans are named after a cave in Siberia where remains of individuals were first unearthed.
Scientists were able to extract enough DNA from bones and teeth to show they were a distinct branch of humans. A few other fossilized specimens have since been discovered across Central Asia including Tibet, showing they were capable of surviving at high altitudes.
Researchers say primitive hominins interbred with modern humans in the distant past. The new study identifies the Philippines as the hotbed of this integration. Papuan Highlanders were previously thought to be the biggest carriers of Denisovan genes.
Revealing the complex history of mankind
An international team analyzed around 2.3 million mutations from 118 ethnic groups of the islands. They were from diverse populations of Negritos populations as well as Papuans.
“Together with the recent discovery of a small-bodied hominin, called Homo luzonensis, the data suggest there were multiple archaic species that inhabited the Philippines prior to the arrival of modern humans,” Dr. Larena says in a statement to SWNS. “These groups may have been genetically related.”
The findings shed fresh light on a complex intertwined history of modern and archaic humans in the Asia-Pacific region. Distinct Denisovan populations interbred with incoming Australasians across multiple locations and at various points in time.
“By sequencing more genomes in the future, we will have better resolution in addressing multiple questions, including how the inherited archaic tracts influenced our biology and how it contributed to our adaptation as a species,” Larena concludes.
The study appears in the journal Current Biology.
South West News Service writer Mark Waghorn contributed to this report.