The rise of the renowned ancient Mayan civilisation of Mexico and central America was fuelled by contact with outsiders, as seen in ancient DNA.
That’s according to new research by a Trinity College Dublin (TCD) geneticist reported today in the journal Current Biology.
Scientists previously found that present day Maya people carry genes from both the traditional local Maya ancestors and Mexican highlanders.
“What makes our findings significant is that we identified this gene flow starting around the beginning of the Classic period,” said Shigeki Nakagome, Ussher Assistant Professor in Genomic Medicine, School of Medicine, TCD.
The Classic period of Mayan civilisation – when it was at its peak – scholars say was from around 250 AD to 950 AD, after which it declined.
“Archaeological evidence has long suggested that a possible connection between the Classic Maya states and regions in highland Mexico,” said professor Shigeki.
“This suggests that interaction between these regions may have played a role in the rise of Classic Maya civilisation.”
The civilisation flourished primarily in present-day southeastern Mexico, Guatemala, Belize, and parts of Honduras and El Salvador.
At its height, the Mayans built cities which were huge by the standard of the time, made up of monumental stone structures, and pyramid temples.
They became renowned for a sophisticated writing system, advances in mathematics and astronomy, and skill in crafts like sculpture and pottery.
“Despite extensive archaeological research, many aspects of their ancestry and population history remain poorly understood,” said Prof Nakagome.
The TCD researchers used ancient genomics to analyse DNA from seven people who lived in Copán in Honduras during the Classic Mayan period.
Ancient genomics is the study of genomes (a genome being the entire DNA in a single cell) recovered from the bones or teeth of ancient people.
This enabled them to investigate the genetic ancestry of these individuals.
“We focused on the petrous portion of the temporal bone, a dense part of the skull known for its exceptional DNA preservation.”
This area of bone is known to yield higher quantities of ancient DNA compared to other parts of the human skeleton.
However, Nakagome and his team found that studying these ancient DNA samples was far more difficult than investigating modern DNA.
“After death, DNA begins to degrade and fragment due to environmental factors like temperature, humidity, and microbial activity.
“As a result, ancient DNA is often highly fragmented, chemically modified and present in very low quantities, requiring specialised techniques and strict contamination controls to recover and analyse it accurately.”
The results indicated that there was an influx of people from Highland Mexico into the Mayan lowland areas during the early to middle Classic period.
“This shows that the rise of the Classic Maya civilisation involved movement and interaction with people possibly from outside the Maya region.”
The research also sheds some light on the fall of the Mayan people, beginning around 900 AD, which remains a famous and enduring scientific mystery.
“As the Mayan civilisation began to collapse near the end of the classic period, we saw signs of a population decline.”
“This genetic evidence helps support the idea that major social and environmental changes had real demographic consequences.”
The TCD researchers now plan to study more DNA from other ancient skeletal remains of people across a variety of locations in the Mayan world.
This data will be compared to the archaeological and environmental historical record to gain further insights into the rise and fall of the Mayans.
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