NEW YORK – New research has revealed the population relationships and migrations that took place in the central Mediterranean during the Iron Age as maritime technology and more far-flung migrations became possible.
"By integrating our research questions across the populations of the central Mediterranean, we describe here how increasing rates of mobility across the Mediterranean contributed to the genetic history of the region," co-senior and co-corresponding authors Jonathan Pritchard, a genetics researcher at Stanford University and Harvard Medical School, and Ron Pinhasi, an evolutionary anthropology researcher affiliated with the University of Vienna and the University of Chicago, and their colleagues wrote in Nature Ecology & Evolution on Thursday.
Using shotgun sequencing, the researchers generated low-coverage whole-genome sequences for 30 Bronze or Iron Age individuals at four coastal or port sites in present-day Tunisia, Sardinia, and central Italy. From there, they analyzed the genomes alongside published sequences from other modern or ancient individuals, including dozens of Iron Age Sardinians and central Italians.
"Archaeogenetic research adds a new line of evidence to our understanding of the people and their interactions during this dynamic period," the team noted.
Past research has shown that central and western parts of the Mediterranean were home to colonies and trade routes founded by Greek and Phoenician/Punic city-states, the researchers noted, while sites in central and northern Italy were home to Etruscan-speaking city states. Even so, not as much was known about the region's population genetics during the late Bronze and early Iron Age.
"The first millennium BCE was characterized by a marked increase in mobility in the Mediterranean," the authors explained. "Advances in sailing and seafaring allowed for easier and more frequent travel across the open sea, facilitating new networks of interaction for trade, colonization, and conflict."
In their current analyses, the investigators demonstrated that the central Mediterranean was home to populations with a combination of local and non-local ancestry, reflecting migrations and other ties between populations in the region in the Iron Age.
"These results highlight both the role of local populations and the extreme interconnectedness of populations in the Iron Age Mediterranean," the authors reported. "By studying these trans-Mediterranean neighbors together, we explore the complex interplay between local continuity and mobility that shaped the Iron Age societies of the central Mediterranean."
Consistent with the interrelationships identified from archaeological clues and historical records, the team unearthed widespread genetic heterogeneity in Iron Age populations in the Mediterranean, along with shifts in ancestry at Iron Age sites in North Africa and Sardinia relative to that found during the Bronze Age.
Iron Age samples in Tunisia and Sardinia were marked by an uptick in ancestry from Yamnaya Samara, Moroccan Neolithic farmer, Anatolian Neolithic, and Iranian Neolithic populations, for example. On the other hand, while samples from Italy showed more Bronze Age to Iron Age continuity than those in other sites, the proportions of Yamnaya Samara, western hunter-gatherer, Anatolian Neolithic, Iranian Neolithic, and Moroccan Neolithic ancestry shifted over time.
"The Iron Age in the Mediterranean was characterized by leaps in the ease of seafaring and, consequently, mobility," the authors explained. "We see that these technological changes were accompanied by an increase in gene flow and genetic mobility across the Mediterranean, which shaped the ancestry makeup of the populations on its shores."