New research sheds light on the link between a different 'homo' species and humans living today.
About 12 years ago, scientists discovered a new species of "small" humans that they called Homo floresiensis and dubbed "hobbits" due to their short stature.
The name Homo floresiensis comes from the Indonesian "Flores Island," from which the fossil skeletons of the species were unearthed in 2004.
Researchers believe that H. floresiensis were at the peak of their evolution about 13,000 years ago. However, we do not currently understand their relationship to modern humans.
That said, modern DNA sequencing techniques can be valuable tools that allow us to solve ancient — and modern — mysteries.
In a bid to understand the genetic relationship between these tiny, hobbit-like beings and modern humans, an international team of researchers analyzed the genetic makeup of the H. floresiensis and compared it with that of another group with short stature: a pygmy population that lives in Flores.
Richard E. Green, an associate professor of biomolecular engineering at the University of California Santa Cruz, is the corresponding author of the study that details the findings.
Green and his colleagues published their paper in the journal Science.
Height and diet genetic variants found
Green and his colleagues examined the genomes of 32 of these pygmy people to see whether there were any genetic links with H. floresiensis.
The researchers scanned the pygmies' gene set for any traces of DNA from a shared human lineage. Specifically, they looked at genes that may be responsible for height in Europeans.
This was the first time that scientists had access to DNA from H. floresiensis.
Firstly, in the pygmy population, Green and team found a large number of variations in the genes responsible for short stature. The researchers explain what this means.
"It means," says Green, "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."
Secondly, the analysis found genetic evidence of a change in diet of the pygmy people at some point in the history — namely, the researchers found genetic variants that encode a type of enzyme called fatty acid desaturase enzymes.
These enzymes are key for the metabolism of fatty acids. Discovering these genetic variants, Green explains, "suggests that something in the past caused [the pygmies'] diet to change dramatically, and they adapted by natural selection favoring certain variants of those genes."
Hobbits and modern people: No link found
Most importantly, the analysis did not find any genes that might have been inherited from the H. floresiensis population.
"If there was any chance to know the hobbit genetically from the genomes of extant humans, this would have been it. But we don't see it. There is no indication of gene flow from the hobbit into people living today."
Richard E. Green
Peter Visscher, from the University of Queensland in Brisbane, Australia, says that the study he co-authored helps answer vital questions about human adaptation.
"Just as livestock breeding happens through small changes in gene frequencies at very many loci, human adaptation works by exploiting the pool of polygenic variation available for selection," the researcher says.
It is intriguing that both the H. floresiensis and the pygmy populations evolved to have decreased height, but they do not share much else. So, the origins of the so-called hobbit continue to be a mystery.