Identifying genetic traces of historical expansions: Phoenician footprints in the Mediterranean

Abstract

The Phoenicians were the dominant traders in the Mediterranean Sea two thousand to three thousand years ago and expanded from their homeland in the Levant to establish colonies and trading posts throughout the Mediterranean, but then they disappeared from history. We wished to identify their male genetic traces in modern populations. Therefore, we chose Phoenician-influenced sites on the basis of well-documented historical records and collected new Y-chromosomal data from 1330 men from six such sites, as well as comparative data from the literature. We then developed an analytical strategy to distinguish between lineages specifically associated with the Phoenicians and those spread by geographically similar but historically distinct events, such as the Neolithic, Greek, and Jewish expansions. This involved comparing historically documented Phoenician sites with neighboring non-Phoenician sites for the identification of weak but systematic signatures shared by the Phoenician sites that could not readily be explained by chance or by other expansions. From these comparisons, we found that haplogroup J2, in general, and six Y-STR haplotypes, in particular, exhibited a Phoenician signature that contributed > 6% to the modern Phoenician-influenced populations examined. Our methodology can be applied to any historically documented expansion in which contact and noncontact sites can be identified.

Figure 1

Geographical context of the Phoenician and Greek expansions (A) Maritime expansions of the Phoenicians (11^th century BCE) and Greeks. Red: Phoenicia, Phoenician colonies; pink: Phoenician trading posts; blue: Greece and Greek colonies. (B) J2 haplogroup frequency comparisons between Phoenician contact regions (thick borders) and nearby non-contact regions (thin borders). Lines indicate paired haplogroup comparisons between two sites. An ellipse indicates a site with multiple population samples. Colored circles indicate the higher haplogroup J2 frequency site in each pair. (C) Phoenician Colonization Signal 1 (PCS1+) haplotype frequency comparisons between Phoenician contact regions (thick borders) and nearby non-contact regions (thin borders). Lines indicate paired haplotype comparisons between two sites. An ellipse indicates a site with multiple population samples. Colored circles represent the higher PCS1+ frequency site in each pair. (D–F) Geographical distribution of the PCS1+ (D), PCS2+ (E), and PCS3+ (F) haplotypes in the Mediterranean region. The PCS+ central haplotypes are shown in Table 2. Higher color intensities indicate higher haplotype frequencies; absolute frequencies are given in Table 3. Note the highly enriched coastal and island distribution of these haplotypes and the prominence of all in the Levant.