Matthew Williams, assistant professor of biology, and his student, Aidan Richards, led an international ancient DNA study that sheds new light on the relationship between genetic diversity, cultural change, and resettlement in ancient Mesopotamia.
The study, titled “Mesopotamian ancient DNA reveals Iron Age integration of heterogeneous Bronze Age genetic ancestries,” was published in Genome Biology, and examined ancient DNA from Bakr Awa, a prominent archaeological site connecting the Mesopotamian plains and the Zagros Mountains.
Williams said the study found that the borderlands between Mesopotamia and Iran during the Bronze Age were a true regional crossroads, reflected in both genetic and cultural diversity. The research also suggests that a later shift in societal structure during the Iron Age resulted in the integration of diverse Bronze Age genetic ancestries rather than their replacement.
Ancient Mesopotamia is famous as a cultural “melting pot,” but Williams said the new research shows that its genetic landscape was just as dynamic. Following a devastating fire and later resettlement at Bakr Awa, the incoming Iron Age population appears to have integrated the site’s diverse Bronze Age lineages instead of replacing them.
The finding demonstrates that major cultural shifts do not always require large-scale population turnover.
“On a scientific level, this manuscript represents the culmination of my interdisciplinary training,” Williams said. “It applies a philosophy that synthesizes biological, genetic, and cultural knowledge to reconstruct the human past rather than treating these disciplines as distinct or even antagonistic.”
The project brought together an international research team featuring scientists from Australia, Poland, and Germany. It also included an important contribution from WWU sophomore biology student Aidan Richards, who used Python to analyze genetic data, determine degrees of relation, and study runs of homozygosity among ancient Bakr Awa individuals.
Runs of homozygosity are long, identical segments of DNA that can indicate close-kin mating or population isolation. Richards’ analysis revealed a near-complete absence of long homozygous stretches of DNA, providing additional biological evidence that Bakr Awa’s cultural diversity was reflected in its genetic diversity.
“It was always a Eureka moment when I got the code to work and make the right figures,” Richards said. “But the best takeaway was working under Dr. Williams. He was so good at explaining complex genetic topics and how different code analyzes the data differently.”
Richards said the project gave him meaningful exposure to population genetics, an area he hopes to continue learning about as he prepares for a future in medicine.
“I hope to go into medicine where I can learn more about genetics,” Richards said. “Being involved in this project exposed me to population genetics. I think I will always have an interest in population genetics.”
For Williams, the project was both a scientific milestone and a personally meaningful experience. Mesopotamia has captivated his intellectual curiosity since childhood, and the study allowed him to apply his interdisciplinary approach to a region he has long found fascinating.
The project also helped Williams feel rooted in the WWU community during his first year as a faculty member. He first connected with Richards at a biology club lunch event, where the two discovered a shared interest in skateboarding. Richards later became the first student to join Williams’ research lab at WWU.
“When Aidan formally decided to join my lab, this was the moment that truly solidified my sense of belonging here at WWU,” Williams said.
Richards said working with Williams became one of the highlights of his year.
“My experience working with Dr. Williams has become a highlight of my year,” Richards said. “He is a great mentor and role model who I felt I could relate to.”
Read the full Genome Biology article on their website. To learn more about biology programs and student research opportunities at Walla Walla University, visit wallawalla.edu/biology.
Posted June 22, 2026
