[Image description: A sun-kissed landscape with towering trees, sparkling rivers, and vast plains stretching out to the horizon. In the foreground, a group of early humans are seen huddled around a fire, roasting meat on skewers while others are busy gathering fruits and berries from nearby bushes. Nearby, a Neanderthal individual is spotted, using a crude stone tool to scrape off flesh from a freshly hunted mammoth carcass. The two groups seem to be living in harmony, with some members of each group occasionally interacting and exchanging goods or stories.]

The Princeton study, led by Joshua Akey, has uncovered new layers of the shared history between early humans and Neanderthals. Using a genetic tool called IBDmix, the researchers mapped gene flow between the hominin groups over the past quarter-million years, revealing multiple waves of contact and interbreeding.

“We now know that for the vast majority of human history, we’ve had a history of contact between modern humans and Neanderthals,” said Akey. The results of their work were published in the journal Science, challenging previous genetic data that suggested modern humans evolved in Africa 250,000 years ago and then dispersed out of Africa 50,000 years ago.

The study found evidence of three main waves of contact: one about 200-250,000 years ago, another around 100-120,000 years ago, and the largest wave about 50-60,000 years ago. This contrasts sharply with previous research that suggested modern humans stayed put in Africa for 200,000 years before dispersing out.

The researchers also discovered that Neanderthals had a smaller population than previously thought, with estimates revised from around 3,400 individuals to roughly 2,400. This finding helps explain how Neanderthals disappeared from the fossil and genetic record around 30,000 years ago.

Akey’s team found strong evidence consistent with Fred Smith’s hypothesis that Neanderthals were largely absorbed into modern human communities rather than going extinct. “Our results provide strong genetic data consistent with Fred’s hypothesis, and I think that’s really interesting,” said Akey.

The study provides a new understanding of the complex relationship between early humans and Neanderthals, highlighting the importance of interbreeding and cultural exchange in shaping human evolution.

The discovery of Te K’ab Chaak’s tomb, the first identifiable ruler’s tomb found in over four decades of work in Caracol, has rewritten Mesoamerican history. The tomb, located at the base of a royal family shrine, contained 11 pottery vessels, carved bone tubes, jadeite jewelry, a mosaic jadeite mask, Pacific spondylus shells, and other perishable materials.

One vessel portrayed the image of Ek Chuah, Maya god of traders, surrounded by offerings. Four of the pottery vessels depicted bound captives, similar to those found in two related burials. Two vessels supported lids with modeled handles of coatimundi (tz’uutz’ in Maya) heads.

The Chases estimate that at the time of his burial, Te K’ab Chaak was an advanced age and approximately 5’7″ in height, with no remaining teeth. Their investigations at Caracol’s Northeast Acropolis revealed three burials interred in the area, all dated to AD 350, a generation before the previously recognized Teotihuacan presence in the Maya area.

These findings demonstrate that early Maya rulers were fully enmeshed in Mesoamerican-wide contacts prior to the Teotihuacan entrada recorded on Maya monuments. The connections between the two regions were undertaken by the highest levels of society, suggesting that initial kings at various Maya cities, such as Te K’ab Chaak at Caracol, were engaged in formal diplomatic relationships with Teotihuacan.

The royal dynasty established by Te K’ab Chaak continued at Caracol for over 460 years. The Chases’ findings also indicate that ancient peoples in the new world were travelers, with a trip between Teotihuacan and Caracol today taking over 23 hours by car, or approximately 153 days on foot.

Research continues on the contents of the chamber, including the reconstruction of the jadeite death mask and ancient DNA and stable isotope analysis of the skeletal material. The Chases will present results of the 2025 Caracol field season at a conference on Maya-Teotihuacan interaction hosted by the Maya Working Group at the Santa Fe Institute in August 2025.

The Ancient Roots of Disease: Scientists Uncover 214 Prehistoric Pathogens in Human DNA

A groundbreaking study published in Nature has revealed that prehistoric humans were plagued by a staggering 214 ancient pathogens, dating back as far as 6,500 years ago. The research team, led by Professor Eske Willerslev from the University of Copenhagen and the University of Cambridge, analyzed DNA from over 1,300 prehistoric individuals, including those up to 37,000 years old.

This extensive study is the largest to date on the history of infectious diseases and sheds new light on the development of diseases caused by bacteria, viruses, and parasites. The findings suggest that humans’ close cohabitation with domesticated animals, particularly from the Pontic Steppe, played a significant role in the spread of these ancient pathogens.

One of the most striking discoveries is the presence of the plague bacterium Yersinia pestis, which was identified in a 5,500-year-old sample. This is the world’s oldest genetic trace of the disease that ravaged Europe during the Middle Ages, killing between one-quarter and one-half of the population.

The implications of this study are far-reaching and could have significant consequences for vaccine development and our understanding of how diseases arise and mutate over time.

Associate Professor Martin Sikora, the study’s first author, emphasized that “if we understand what happened in the past, it can help us prepare for the future, where many of the newly emerging infectious diseases are predicted to originate from animals.” This knowledge is crucial for developing effective vaccines and ensuring that current ones provide sufficient coverage or need to be updated due to mutations.

The study was made possible by funding from the Lundbeck Foundation. This research highlights the importance of understanding our shared history with ancient pathogens and serves as a reminder of the urgent need to develop targeted solutions for emerging infectious diseases.