Ancient DNA reveals that the Mayans sacrificed pairs of twins in their rituals

About a thousand years ago, in the ancient city of Chichen Itza on the Yucatan Peninsula, in what is now Mexico, the Mayans performed human sacrifices that included twin brothers. This is the main revelation of a work published this Wednesday in the journal Nature And in which a team of paleogenetic scientists led by the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) examined ancient DNA from 64 sacrificed individuals found in an underground chamber.

Chichen Itza, which emerged as a center of power at the end of the Classic Maya period, was one of the largest and most influential cities of ancient Mesoamerica, but many of the ritual ceremonies celebrated by its inhabitants are unknown in detail. The new work focuses on an underground well of the ancient city where the remains of more than a hundred young children were found in 1967. These bones were preserved at the Center for Yucatan Studies of the National Institute of Anthropology and History (INAH), as the well was buried by some works and today is located under an abandoned landing strip.

Since it involved the expansion of a water cistern, a structure known as a chultun that is associated with rain, the belief was long widespread that it was a mass sacrifice of girls to alleviate drought. But examination of the genetic material has revealed a surprise.

Sacrifice and resurrection

“Our work shows that all 64 individuals buried in the chultun were male infants and that there were two pairs of twins,” Rodrigo Barquera, immunogeneticist at the MPI-EVA and lead author of the study, told elDiario.es. Since twins appear spontaneously in only 0.4% of births, the presence of two pairs in the chultun is much more than would be expected by chance and indicates a clear preference for these siblings. Also, the researchers highlight that this presence suggests a connection with the origin myths of the Popol Vuh, the sacred text of the Mayans in which the sacrifice of twins is a central theme.

In this religious text, the twins Hun and Vucub Hunahpu descend to the underworld and are sacrificed by the gods after their defeat in a ball game. Hun Hunahpu’s twin sons, known as the Hero Twins, avenge their father and uncle by subjecting themselves to repeated cycles of sacrifice and resurrection in order to outwit the gods of the underworld.

Analysis shows each pair of twins were sacrificed at the same time

“The analysis shows that each pair of twins was sacrificed at the same time, but the 64 children analyzed died over a period of 500 years,” explains Barquera. According to the expert, this is the first evidence of the sacrifice of twins in any civilization, and they now propose to investigate two other similar chultuns at the sites. Uxmal And Mayapan“Of course in other cultures twins were associated with other kinds of symbolism, but none that we know of where they were sacrificed,” he explains.

selected for the ceremony

This new result contrasts with what was previously documented in the Sacred Cenote of Chichen Itza, where both young women and boys and girls were found, possibly sacrificed to boost crop yields and ask the gods to send rain. “In the case of Chultun, we believe that the sacrifice has nothing to do with drought and that it is another type of offering that is probably related to fertility or a more cosmological vision to honor their gods,” says Barquera.

“Early 20th-century accounts propagated false stories about young women and girls sacrificed at the site,” says Christina Warriner, associate professor at Harvard University and group leader in the MPI-EVA. “This study turns that narrative upside-down and reveals deeper connections between ritual sacrifice and the cycles of human death and rebirth described in sacred Maya texts.”

Dating of the remains showed that the chultun was used for mortuary purposes between the 7th and 12th centuries, but most of the children were buried during the 200-year period of Chichen Itza’s political heyday between 800 and 1000 AD. C. Genetic analysis shows that the children came from the local Maya population and that at least a quarter of them were closely related and consumed a similar diet, which suggests that they were raised in the same household. This led the authors to the conclusion that related male children were probably being selected in pairs for ritual activities associated with the chultun.

Our findings show remarkably similar dietary patterns among individuals displaying first- or second-degree familial relationships.

“Our findings show remarkably similar dietary patterns among individuals who display either first- or second-degree familial relationships,” he says. Patxi Perez-Ramalloco-author of the study. “The similar age and diet of the male children, their close genetic relationship and the fact that they were buried in the same place for more than 200 years point to the chultun as a post-sacrificial burial site, with the sacrificed individuals having been selected for a specific reason,” he says. Ona del Castillo-ChavezCo-author and researcher in the Physical Anthropology Section of the INAH Yucatán Center.

In the footsteps of salmonella

One of the most interesting aspects of the new work is that it has allowed us to compare the genomes of these populations with those of the local Mayan community of Tixcaltuyab, which, according to Barquera, has remained quite stable despite so much time having passed. In the comparison, the researchers find relevant genetic changes that tell us about possible adaptations to selective pressure factors such as infection by bacteria. Salmonella

, “The immune response to this disease is a series of genes that appeared with a frequency of 25% in these children and today are at 45%, that is, they have almost doubled the frequency, which tells us that there is a selection process, explains the expert.

During the 16th century, in Mexico, diseases brought by Europeans, such as poisoning associated with food consumption, contributed to a reduction of up to 90% of the local population. The most serious epidemic was that of cocoliztli in 1545, caused by a recently identified pathogen Salmonella enterica Paratyphi C. “Empirically we already knew that there is resistance to Salmonella in Mexico. I had this hypothesis before, because we had seen this variant in Latin American populations, but it didn’t make any sense that it was by chance,” Barquera stressed.

This is not an accidental discovery

Vanessa Villalba, a researcher at the Institute of Evolutionary Biology (IBE) who has not participated in the study, believes that the results are surprising because they report a clear selection of these children, who are similar in age and sex. “Probably also from a certain number of families that made up the community, given the high degree of close kinship found in the sample,” he says. Villalba emphasizes that the confirmation that these are two pairs of twins could not have been achieved without paleogenetic analysis and denies that this is a chance discovery. “We know that twins are born at the same time, but they do not necessarily die at the same time,” he explains. “The fact that this is the case clearly indicates a deliberate act of sacrifice in a joint event.”

Gemma Marfany, Professor of Genetics at the University of Barcelona (UB), highlighted the quality of the genetic analysis and said that the authors have taken care of details such as analyzing a single bone so as not to be confused with the genetic assignment of the remains and to be able to ensure that they have two pairs of monozygotic twins without fear of error. And, above all, the bioethical commitment of the authors seems worthy of applause. “They have achieved an agreement to transfer community DNA and the population has agreed as a whole to transfer the DNA of some of its members to carry out specific genetic research,” she said. “Let’s remember that genetic information is sensitive and can be used to stigmatize a population, so this is a bioethical requirement in this type of research.”

For anthropologist Goeffrey Braswell of the University of California San Diego (UCSD), the fact that such a large sample has been the subject of such detailed DNA work is encouraging and he believes it could help to better understand the social and political structures of these populations. He believes this is the first proven case of the sacrifice of twins, although he believes that the justifications of the Popol Vuh do not make sense and appeals to a simpler explanation: that these pairs of brothers were a simple way to obtain resources for sacrifice. “I think this work really emphasizes the importance and widespread practice of child sacrifice for rain/agricultural rituals throughout Mesoamerica over a period of at least 3,000 years,” he concludes. “When there is a drought and they cannot produce food, people take desperate measures and often sacrifice their most beloved thing: children.”