The Atacama "Alien" Skeleton: What DNA Tests Really Showed

The so-called Atacama "alien" is a human being. The tiny mummified skeleton, nicknamed Ata, was found in Chile's Atacama Desert in 2003 and measures only about 15 centimetres (6 inches). DNA tests published in 2013 and 2018 showed that it belonged to a girl of local indigenous South American ancestry, and most researchers now agree she was a fetus who was stillborn or died very soon after birth. Nothing about her points to an origin beyond Earth. What remains disputed is narrower: whether she really had unusual bone disorders, and whether she should have been studied at all.

The mummified remains known as Ata: about 15 cm long, with a long, pointed skull and ten pairs of ribs.

Where the skeleton came from

Ata was found in 2003 near La Noria, an abandoned nitrate-mining town in the Atacama, one of the driest places on the planet. The man who found her, Oscar Muñoz, sold the remains, and after passing through other hands they ended up with a Spanish businessman, Ramón Navia-Osorio, who still owned them when the scientific papers appeared.

Extreme dryness is the reason she survived at all. In the Atacama, soft tissue can dry out before it rots, which is why the desert is famous for natural mummies thousands of years old. Ata turned out to be far younger than that: dating places her death as recently as the late 1970s, and her DNA was in good enough condition to be read in detail.

Why people thought it was an alien

At first glance the body does not look like a typical newborn. The skull is long and tapers to a point, the face looks compressed, and the chest has ten pairs of ribs rather than the usual twelve. Photos circulating online around 2009 and 2012 made those features look even stranger, with no scale and no medical context.

The alien story took off when UFO researcher Steven Greer, founder of the Disclosure Project, arranged for X-rays and CT scans in Spain in 2012 and featured Ata in his 2013 film Sirius. The film presented the remains as a possible extraterrestrial or hybrid. The scans themselves were useful: they showed traces of organs inside the chest, and a radiologist who reviewed them judged the bones to look about as mature as a six-year-old's. That single observation, a fetus-sized body with "old" bones, became the core of the mystery.

What the DNA tests showed in 2013

Garry Nolan, an immunologist and geneticist at Stanford University, contacted the film's makers and offered to analyse a sample. His team extracted DNA from bone marrow and found, unambiguously, a human genome. Her mitochondrial DNA, which is inherited from the mother, belonged to haplogroup B2, a lineage common among indigenous peoples of western South America. In other words, Ata's mother was almost certainly from the region where she was found.

Early reports noted that roughly 9% of the sequence did not match the human reference genome. That figure was widely misread as evidence of something non-human. It is not. Old samples are degraded and contaminated by bacteria and handling, and short, damaged fragments often fail to map cleanly; a mismatch of that size is what geneticists expect from such material.

The 2018 genome study and its claims

The full analysis appeared on 22 March 2018 in the journal Genome Research, with Nolan and Atul Butte's group at the University of California, San Francisco among the authors. The team reported 64 rare variants in seven genes linked to bone growth and skeletal development, including genes associated with forms of dwarfism, scoliosis and joint malformations. Their interpretation was that a combination of these mutations might explain a body that looked both very small and unusually advanced in bone development.

Nolan put it vividly to National Geographic, saying the child had "rolled the dice seven times snake eyes." He also stressed the human side of the story, noting that someone had kept the body rather than discarding it: "It was their child."

The study settled the alien question but left open why a fetus might show such features. The researchers themselves called her most likely a stillborn or very short-lived newborn, which already rules out the old idea of a six- to eight-year-old child who stayed six inches tall.

The critics' reply: normal fetal development

In September 2018 a team led by bioarchaeologist Siân Halcrow of the University of Otago published a response in the International Journal of Paleopathology. Looking at the published images and measurements, they argued that there was no real evidence of skeletal disease at all. The elongated skull, they said, fits moulding of a soft fetal head during birth and changes after death; the state of the bones is consistent with a fetus; and the rib count and other oddities fall within normal fetal variation or reflect how the body dried out.

If they are right, the genetic variants reported in 2018 may be ordinary rare variation that every genome carries, rather than the cause of a disease the skeleton may not have had. Halcrow's group also questioned how strongly the genomic findings were linked to the anatomy.

Ethics: a body that was bought and sold

The sharper part of the critique was ethical. Ata is the body of a recently deceased infant, taken out of Chile and sold privately, studied without consent from any family or descendant community. Critics argued that scientific journals should not publish research on human remains with that history. Genome Research replied that its ethics rules had not anticipated specimens of uncertain origin and promised to review its policies. The authors accepted the criticism, said senior team members never handled the remains themselves (they received a bone sample of about one cubic millimetre), and joined calls for Ata to be returned to Chile and buried.

Nolan was blunt about the trade that put the body in front of cameras, telling National Geographic that people should not be "trafficking in human bodies and claiming they're aliens" for money.

Myths that still circulate

"Ata's DNA was 9% unknown." The unmatched reads reflected degraded, contaminated material, not a foreign genome.
"Ata was a six-year-old who stopped growing." The bone-age estimate came from scans of a fetus-sized body. Both the 2018 authors and their critics treat her as a fetus or newborn.
"Ata is thousands of years old." She died within living memory, possibly in the 1970s, which is part of why the ethical questions matter.
"Science still can't explain it." The open question is about rare disease versus normal fetal anatomy, a medical debate, not an extraterrestrial one.

The lasting lesson of Ata is less about aliens than about how quickly an unexplained photo can outrun the evidence, and how a real child's remains can be turned into a commercial curiosity. Treating her as a person, which is what the researchers on both sides eventually urged, is the most reasonable conclusion of all.

Sources: Wikipedia: Atacama skeleton; National Geographic, 22 March 2018: Mysterious "Alien" Mummy Finally Has a Fascinating Explanation; original article by IFL Science.

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