After five years of genetic research, a mysterious mummified skeleton discovered in Chile’s Atacama desert is now confirmed to be human – quashing theories about its extraterrestrial origins.
Though the results may be disappointing to "I want to believe" types, the complete genome sequencing has yielded fascinating insights into the medical causes of the specimen’s never-before-seen deformities.
According to a study published in Genome Research, DNA extracted from the remains, nicknamed Ata, bears mutations in seven genes associated with bone and facial malformation, premature joint fusion, and dwarfism. Several of the novel abnormal sequences occurred in genes that were previously not known to affect physical development.
The backstory to this now-clarified scientific puzzle began in 2003, when an artifact hunter reportedly dug up Ata, wrapped in a white cloth bundle, from the grounds of an abandoned church in the mining ghost town of La Noria. Quickly picked up by local media outlets, the initial sensationalism around Ata was somewhat justified: Who wouldn’t be shocked by a 15-centimeter (6-inch) tall, cone-headed humanoid skeleton with sinisterly slanted eye sockets and the wrong number of ribs?
Senior author Garry Nolan, PhD, from Stanford University, was immediately fascinated.
"I had heard about this specimen through a friend of mine, and I managed to get a picture of it," Nolan said in a statement. "You can't look at this specimen and not think it's interesting; it's quite dramatic. So I told my friend, 'Look, whatever it is, if it's got DNA, I can do the analysis.'"
His team’s initial investigation, completed in 2013, provided some answers yet also raised new questions. Many had speculated that Ata was an ancient, desiccated premature fetus, but multiple examinations revealed that it is only about 40 years old. Moreover, the state of the specimen’s bones suggested that it died at six to eight years of age.
To definitely determine who (or what) the skeleton is, Nolan enlisted UC San Francisco pediatric genomics expert Atul Butte, MD, PhD.
Their full genetic analysis, which compared Ata’s DNA sequences to those from both healthy and diseased references, proves that Ata is a female of South American descent and strongly implies that she was a pre-term birth with a severe form of skeletal dysplasia and a bone-aging disorder that caused early growth plate fusion.
“While the extraordinary phenotype of the specimen drove broad discussion as to its origin, and no hypothesis was left off the table during analysis, the specimen is shown here to have a purely earthly origin with mutations that reflect the visual determinations,” the paper states.
How a fetus harbored so many genetic defects, however, is likely to remain mysterious considering that no (sane) people have come forward with insider knowledge.
“While we can only speculate as to the cause for multiple mutations in Ata’s genome, the specimen was found in La Noria, one of the Atacama Desert’s many abandoned nitrate mining towns, which suggests a possible role for prenatal nitrate exposure leading to DNA damage.”