The Etruscans: a population-genetic study

Abstract

The origins of the Etruscans, a non-Indo-European population of preclassical Italy, are unclear. There is broad agreement that their culture developed locally, but the Etruscans' evolutionary and migrational relationships are largely unknown. In this study, we determined mitochondrial DNA sequences in multiple clones derived from bone samples of 80 Etruscans who lived between the 7th and the 3rd centuries b.c. In the first phase of the study, we eliminated all specimens for which any of nine tests for validation of ancient DNA data raised the suspicion that either degradation or contamination by modern DNA might have occurred. On the basis of data from the remaining 30 individuals, the Etruscans appeared as genetically variable as modern populations. No significant heterogeneity emerged among archaeological sites or time periods, suggesting that different Etruscan communities shared not only a culture but also a mitochondrial gene pool. Genetic distances and sequence comparisons show closer evolutionary relationships with the eastern Mediterranean shores for the Etruscans than for modern Italian populations. All mitochondrial lineages observed among the Etruscans appear typically European or West Asian, but only a few haplotypes were found to have an exact match in a modern mitochondrial database, raising new questions about the Etruscans' fate after their assimilation into the Roman state.

Figure 1

Map of Italy showing the area of Etruscan influence (gray) in the 7th and 6th centuries b.c., from Barker and Rasmussen (1998). A solid line identifies the boundaries of Etruria proper. Solid circles are sampling locations: A, Adria (17 samples, 5 DNA sequences used for statistical analyses); V, Volterra (6, 3); S, Castelfranco di Sotto (2, 1); P, Castelluccio di Pienza (1, 1); M, Magliano and Marsiliana (25, 6); T, Tarquinia (18, 5); C, Capua (8, 6). Additional samples that yielded no amplifiable DNA were from Castelnuovo Berardenga (1, 0) and Pitigliano (2, 0).

Figure 2

Reduced median network of the haplotypes identified among the Etruscans. Haplotype 5AM is the Cambridge reference sequence (CRS). Circle sizes are proportional to frequencies. Transitions are numbered relative to the CRS (−16,000); 095G is the only transversion. Sites undergoing recurrent mutations are underlined. The alleles shared with modern Tuscans and modern Cornish are highlighted.

Figure 3

Pairwise genetic distances (F_ST × 1,000) and corrected mean pairwise sequence differences between the Etruscans and modern populations of Europe and of the Mediterranean shores. The values referring to the current population of Tuscany are underlined.

Figure 4

Two-dimensional representation of the relationships between populations (MDS plot) based on F_ST distances. Population labels and sample sizes: ETRU: Etruscans, 27; AUST: Austrians, 117; BULG: Bulgarians, 30; DENM: Danes, 32; ESTO: Estonians, 28; FRAN: French, 111; GENO, 108: Northern Germans; GEST: Southern Germans 249; GREC: Greeks, 48; ICEL: Icelanders, 53; ITLA: Ladins of Italy, 20; ITSI: Sicilians, 63; ITSU: Southern Italians, 37; ITTU: Tuscans, 49; PORT: Portuguese, 54; SARD: Sardinians, 72; SP: Spaniards, 74; SPBA: Basques, 106; SPCA: Catalans, 15; SPGA: Gallegos, 92; SWIT: Swiss 72; UK: English, 100; UKCO: Cornish, 69; UKWA: Welsh, 92; ADYG: Adigheians, 50; ARME: Armenians, 42; AZER: Azerbaijanis, 40; CEAS: Central Asians, 100; DRUZ: Druzes, 45; EGYP: Egyptians, 91; INHA: Haviks of India, 48; NEAS: Near Easterners, 42; SYRI: Syrians, 49; and TURK: Turks, 96.