| 6 January 2008
Dwarf gene discovery: explanation for 'hobbit' species?
In a discovery that could help boost understanding of a rare type of dwarfism, researchers announced that they have found a genetic culprit for the condition. But in addition to increasing knowledge of this condition, the researchers' conclusions could also fuel the continuing debate over the origins of a mysterious group of 'hobbits' that walked the earth tens of thousands of years ago.
In the study, released by the journal Science, an international team of researchers led by Anita Rauch of the Institute of Human Genetics in Erlangen, Germany, examined a number of individuals with a condition known as microcephalic osteodysplastic primordial dwarfism type II — or MOPD II for short. What they found was that a key mutation in chromosome 21 likely led to the condition — a finding that represents a first-of-its-kind genetic explanation for this type of dwarfism. "Adults with this rare inherited condition have an average height of 100 centimeters and a brain size comparable to that of a 3-month-old baby, but are of near-normal intelligence," the researchers noted in their article.
Genetic experts not affiliated with the work said the finding offers intriguing hints to the genetic puzzle behind this form of dwarfism. But as interesting as the findings are to geneticists, the researchers' conclusions at the end of the article could have even bigger implications for the 'hobbit' remains, whose discovery was announced in 2004.
On one side of the debate are those who believe that the diminutive hominids that inhabited Flores Island about 95,000 to 12,000 years ago represented an entirely new species of humans. On the other side are those that contend that a genetic abnormality, perhaps like the one revealed in the new study, is responsible — which would mean that the hobbits would simply be the products of a genetic quirk that affected previously recognized species of humans of the period. In short, if the hobbits were found to be merely the product of a gene mutation, they would not be accorded the status of a species.
"It is tempting to hypothesize that the Indonesian diminutive hominids were in fact humans with MOPD II," the researchers noted. "With the identification of the genetic basis of MOPD II, this hypothesis may soon be testable." But, Charles Hildebolt, a physical anthropologist at Washington University who has worked with Florida State University paleontologist Dean Falk in the study of Homo floresiensis, said that many characteristics of Homo floresiensis identified in other research over the past three years defy the conditions brought about by the gene mutation. He said that it would be premature to relegate the existence of Homo floresiensis to a genetic quirk, rather than according them status as a species of their own.
Source: ABC News (3 January 2008)
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