Mummified Inca Boy Sheds Light On Lost Genetic History Of South America

Ancient Incan civilizations are known for their sacrifice rituals, which at the time were thought to represent an incredible honor. DNA recently extracted from mummified remains of a seven-year-old boy sacrificed 500 years ago reveal a bit more about Incan civilizations and changes in ancient lineages since then.

The mummy was originally found in 1985, preserved on the icy heights of Aconcagua Mountain, which sits on the border of Argentina and Chile. The mummified boy was killed during a sacrificial ritual known as capochoca, which the Inca performed to make offerings to the gods. After sequencing the young boy's genome, researchers discovered his DNA signature varies greatly from that of modern South Americans. Researchers suggest the boy belonged to a population of native South Americans that all but disappeared following Spanish colonization of the New World.

"Up to 90% of native South Americans died very quickly," Antonio Salas, lead researcher from the University of Santiago de Compostela, told Science. "You can imagine that a lot of genetic diversity was lost as well." This is especially true in the Americans where the gene pool was significantly altered by the introduction of European and African populations. This makes deciphering ancient linages a bit hazy, but the Aconcagua boy's DNA provides a clear window to 500 years ago.

In the recent study, scientists examined a portion of the boy's lung, from which they were able to extract his complete mitochondrial genome, or rather genes passed down solely from his mother. This revealed a genome unlike any researchers had ever seen, and earned the boy placement in a new South American genetic group dubbed C1bi, which researchers believe arose in the Andes 14,000 years ago.

After running the boy's DNA through a database of genetic code, researchers found only four individuals that likely belong to C1bi, three of which are present-day people from Peru and Bolivia and one ancient person from the Wari empire, which was a Peruvian civilization that predated the Inca by several hundred years.

Thankfully, the mountain's cold, dry environment kept the boy's remains preserved well enough for researchers to examine hundreds of years later. Their study was recently published in the journal Scientific Reports. 

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