DNA Reveals Yemen’s Ancient Crossroads

Recent research, conducted by scientists at Khalifa University in Saudi Arabia, has revealed fascinating details about the genetic makeup of the modern Yemeni population. Working alongside regional and international collaborators, the researchers focused on examining Yemeni DNA to uncover the extent to which ancient migrations from the Levant, Arabia, and East Africa influenced the genetic pool of Yemen today. The results of this study, which were published in Scientific Reports, paint a complex picture of human migration, highlighting the strategic location of Yemen as a crossroads of ancient trade routes and its historical role as a site of cultural and genetic exchanges.

Yemen is situated at the southern tip of the Arabian Peninsula, bordered by the Red Sea to the west and the Arabian Sea to the south. This strategic position made it a key player in ancient trade networks, connecting Africa, the Arabian Peninsula, and the Levant. Over centuries, Yemen was an essential participant in the spice and incense trade, which linked it to cultures as far as ancient Egypt, Sumer, and Dilmun. Furthermore, the region’s connection to Mediterranean civilizations, including Israel, the Phoenicians, and Greece, bolstered Yemen’s significance in regional commerce. As wealth flowed into Yemen through trade, so did enslaved peoples, many of whom came from East Africa. This long history of interactions across such vast regions is thought to have left a profound impact on the Yemeni gene pool, shaping the genetic profile of modern Yemenis.

While there has been interest in Yemen’s ancient genetic history, earlier research often lacked precise insights regarding the timing and origins of these migration events. To address these gaps, the current study focused on genetic data from Yemeni populations, in an effort to pinpoint the markers and timeframes of significant population movements into Yemen. Specifically, the study analyzed 46 whole genomes and 169 genotype arrays from Yemeni individuals and compared them to 351 genotypes from neighboring populations. The primary aim was to detect the influences of migrations from regions such as the Levant, Iran, and East Africa, as well as identifying traces of the ancient “Out of Africa” migration.

The results of the analysis revealed some intriguing findings. The researchers discovered a prominent genetic connection to the Levant through paternal Y-chromosome haplogroups, with J1 being the most common marker. J1 is typically found in populations across Southwest Asia, and its presence in the Yemeni gene pool is indicative of ancient migration from the Levant and surrounding regions along male ancestral lines. This connection to the Levant is thought to be linked to the migrations that took place during the Bronze Age and possibly even earlier. Moreover, the mitochondrial DNA (mtDNA) of the Yemeni population revealed strong African maternal influences, with about one-third of Yemeni samples carrying African-specific mtDNA haplogroups such as L2a1, the most common African haplotype found in Sub-Saharan Africa. This signal suggests substantial gene flow from East Africa, particularly along maternal lines.

Interestingly, genetic analysis also revealed the presence of Neanderthal alleles in the Yemeni population, which aligns with the findings observed in other Arabian populations. These alleles are thought to be relics of early human migrations out of Africa. Similar genetic traces have been found in populations across the Arabian Peninsula and parts of the Middle East, indicating that ancient population movements in this region were more complex than previously thought.

Two significant gene flow events were identified by the researchers, shedding light on major migrations into Yemen over thousands of years. One migration event, which occurred around 5,220 years ago, likely brought genetic contributions from populations in Palestine and surrounding regions, while another migration around 750 years ago involved groups from East Africa. This second migration event is particularly noteworthy, as it likely corresponds to the era of increased trade and the forced migration of enslaved East Africans to the Arabian Peninsula.

Yemen’s involvement in the medieval slave trade is believed to have played a crucial role in shaping its modern genetic composition, especially the maternal contributions from East Africa. The Red Sea slave trade connected Yemen to East Africa, where the practice of enslaving people from the Horn of Africa—especially Ethiopia and Eritrea—was common. While enslaved males were often castrated, enslaved women were subjected to sexual exploitation. Many enslaved women were brought into the households of the wealthy and were integrated into the local population through forced relationships. Under Islamic law, children born from such unions had legal status and were free. This historical context of slavery is important because it helps explain the genetic evidence of a stronger African maternal presence in Yemen, even though the predominant paternal lineages are tied to Arabia and the Levant.

While the study does not explicitly link these genetic findings to slavery, the patterns observed—particularly the strong African maternal haplogroups alongside the Levantine paternal contributions—suggest that the legacy of the East African slave trade could have had a lasting influence on the population’s genetic structure. These practices were extensive, though not often discussed in scholarly research concerning Yemen. It’s only in recent decades that the full scope of Yemen’s role in the slave trade has begun to be better understood. Slavery was formally abolished in Yemen in the 1960s, yet its demographic legacy remains evident in the genetic data.

Examining genetic diversity across Yemen, the study revealed regional differences that align with historical migration patterns. Coastal areas, especially those along the Red Sea, exhibited greater African genetic influences, whereas the more northern, inland regions of Yemen showed a closer genetic relationship with populations from Arabia and the Levant. This geographical divide may not be just a reflection of ancient trade routes or migration pathways, but also mirrors the ongoing socio-political divides within the country today. Yemen is currently embroiled in a long-running civil war, and the genetic distinctions between its coastal and inland populations could parallel the demographic and political fault lines that define the conflict.

The findings from this study contribute significantly to our understanding of human migration patterns in the Arabian Peninsula and surrounding regions. They provide new insights into the historical interactions between different populations and reveal the extent to which trade, migration, and slavery shaped the genetic landscape of Yemen. This research also underscores the complexity of human genetic history and the interconnectedness of populations across regions and time periods.

Modern Yemeni populations are thus not just the product of local isolation, but rather the culmination of millennia of migrations, trade, and cultural exchanges. The genetic evidence tells the story of how Yemen, as a crossroads between Africa, Arabia, and the Levant, became a melting pot of diverse genetic contributions. From the ancient inhabitants who left their traces in Yemen’s gene pool to the medieval migrations during the height of the slave trade, the population today reflects the intertwined history of the Arabian Peninsula, East Africa, and the broader Middle East.

Reference: Andreas Henschel et al, Human migration from the Levant and Arabia into Yemen since Last Glacial Maximum, Scientific Reports (2024). DOI: 10.1038/s41598-024-81615-4