AUG 06, 2018 11:03 AM PDT

Mystery Solved: Modern Pygmies not Related to Ancient Ones

WRITTEN BY: Carmen Leitch

The isolation of islands can have a powerful effect on the genetics of the species that live there. In the case of Flores island, it was known that two groups of pygmies made it their home; one in modern times and one that lived there tens of thousands of years ago and went extinct. But, are they connected? Researchers wanted to answer that question, and it took many years to find out. One problem was a lack of a specimen from the fossils of the ancient 'hobbits,' Homo floresiensis. 

The modern pygmy village, Rampasasa, (left), a modern Rampasasa pygmy wearing the traditional head covering and clothing (center) juxtaposed against a Homo floresiensis reconstruction; pygmy elephants in the Liang Bua cave (right)/ Illustration by Matilda Luk, Office of Communications, Princeton University

A team of researchers led by Joshua Akey, a professor of ecology and evolutionary biology and the Lewis-Sigler Institute for Integrative Genomics at Princeton University has addressed that problem. They created a tool that can identify archaic sequences in modern genomes.

"In your genome, and in mine, there are genes that we inherited from Neanderthals," explained Serena Tucci, a postdoctoral research associate in the Akey lab. "Some modern humans inherited genes from Denisovans [another extinct species of humans], which we can check for because we have genetic information from Denisovans.

"But if you want to look for another species, like Floresiensis, we have nothing to compare, so we had to develop another method: We 'paint' chunks of the genome based on the source. We scan the genome and look for chunks that come from different species -- Neanderthal, Denisovans, or something unknown."

She was able to apply their technique to genetic material from 32 pygmies living in Indonesia, near the Liang Bua cave on Flores Island. That’s close to where the fossils of H. floresiensis were discovered in 2004.

This figure shows the relative heights of a modern Indonesian (5' 2), a modern pygmy living on the island of Flores (4' 10) and Homo floresiensis (3' 5, which is the height of an average American 4-year-old). /Credit: Courtesy of Dr. Serena Tucci, Department of Ecology and Evolutionary Biology, Princeton University

"They definitely have a lot of Neanderthal," said Tucci, the first author of a report on this work in the journal Science. "They have a little bit of Denisovan. We expected that, because we knew there was some migration that went from Oceania to Flores, so there was some shared ancestry of these populations."

They did not find any chromosomal chunks with unknown origins.

"If there was any chance to know the hobbit genetically from the genomes of extant humans, this would have been it," added corresponding author Richard "Ed" Green, an associate professor of biomolecular engineering at the University of California-Santa Cruz (UCSC). "But we don't see it. There is no indication of gene flow from the hobbit into people living today."

They did find that there were evolutionary changes linked to diet and short stature. Height has been shown to be a heritable trait, and the pygmies carried many genetic variants associated with shorter height.

"It sounds like a boring result, but it's actually quite meaningful," Green noted. "It means that these gene variants were present in a common ancestor of Europeans and the Flores pygmies. They became short by selection acting on this standing variation already present in the population, so there's little need for genes from an archaic hominin to explain their small stature."

Their genes also showed changes based on their diet, with an enrichment of genes linked to the consumption of a lot of fish. Such changes have been seen in the Inuit,  for example.
 
We know that  H. floresiensis was much smaller than modern Flores pygmies, going from an average of 106 to 145 centimeters. There were also changes in their wrists and feet. It’s not surprising that such changes would be seen on an island, where species can often become giant or small.

"Islands are very special places for evolution," Tucci said. "This process, insular dwarfism, resulted in smaller mammals, like hippopotamus and elephants, and smaller humans."

The work has indicated that the dwarf populations arose independently on the island at least twice. ”This is really intriguing, because it means that evolutionarily, we are not that special," added Tucci. "Humans are like other mammals; we are subject to the same processes."

The video above from the Penn Museum discusses the hobbits of Flores island.

Sources: AAAS/Eurekalert! Via Princeton University, Science

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 30, 2021
Microbiology
Malaria Parasite Seems to be Evolving to Evade Diagnostic Tests
SEP 30, 2021
Malaria Parasite Seems to be Evolving to Evade Diagnostic Tests
When health officials are trying to control a disease outbreak, diagnostic tests can be a crucial tool that provides inf ...
OCT 10, 2021
Cell & Molecular Biology
DNA Can Reveal Treatments for Lung Cancer in 'Never-Smoked' Patients
OCT 10, 2021
DNA Can Reveal Treatments for Lung Cancer in 'Never-Smoked' Patients
There is a well-known causal connection between smoking and lung cancer, and most research on lung cancer has been focus ...
NOV 03, 2021
Plants & Animals
A Samoan Plant May Reduce Inflammation as Well as Ibuprofen
NOV 03, 2021
A Samoan Plant May Reduce Inflammation as Well as Ibuprofen
To the people of Samoa, the medicinal qualities of a tree known as matalafi are well known. Now scientists are bringing ...
NOV 18, 2021
Health & Medicine
What is TurboKnockout® Gene Targeting Technology?
NOV 18, 2021
What is TurboKnockout® Gene Targeting Technology?
Cyagen's innovative TurboKnockout(R); technology is an advanced version of ES cell-mediated gene targeting, which has sh ...
NOV 22, 2021
Genetics & Genomics
Revealing the Battle Between Organisms & Selfish Genetic Elements
NOV 22, 2021
Revealing the Battle Between Organisms & Selfish Genetic Elements
Evolution has allowed organisms to adapt to their environments, sometimes in very specific ways, through changes in thei ...
NOV 26, 2021
Genetics & Genomics
Genetic Analysis Reveals Ongoing Evolution in Europeans
NOV 26, 2021
Genetic Analysis Reveals Ongoing Evolution in Europeans
The biology of organisms can be affected by environmental pressures through the genome. For example, if a genetic mutati ...
Loading Comments...