Population history of southern Italy during Greek colonization inferred from dental remains

Abstract

Objectives:We are testing competing scenarios regarding the population history of the ancient Greek colonization of southern Italy using dental phenotypic evidence. Materials and Methods:We collected dental metric and nonmetric trait data for 481 human skeletons from six archaeological sites along the Gulf of Taranto, dating to pre-colonial (900-700 BC) and post-colonial periods (700-200 BC). We are evaluating scenarios through an individual-level biodistance analysis using a three-pronged approach: (a) by analyzing levels of mobility in pre-and post-colonial periods under a model of isolation-by-distance; (b) by quantifying differences in group means and variances in pre-and post-colonial periods utilizing permutational multivariate analysis of variance and Betadisper analyses; and (c) by identifying ancestries of post-colonial individuals using naïve Bayes classification. Results: Southern Italy during pre-colonial times was characterized by low levels of mobility and marked differences in group means and variances. During post-colonial times, mobility increased and there were no differences in group means and variances. About 18% of the people in post-colonial times were of Greek ancestry and lived equally distributed across Greek colonies and indigenous villages. Nevertheless, the overall biological composition and variability of southern Italy remained relatively unchanged across pre-and post-colonial periods. Discussion: Our results support a scenario in which only few Greek colonists migrated to southern Italy and lived in smaller numbers alongside indigenous people in Greek colonies as well as in indigenous villages. Our results contradict a scenario in which large numbers of Greek invaders founded biologically isolated and substantially homogeneous colonial enclaves within conquered territories.

Testing the utility of dental morphological trait combinations for inferring human neutral genetic variation

“…Third, we used a phenotypic distance statistic for measuring between-population variation that is assuming complete independence among traits. Although it has been repeatedly shown that correlations among dental traits recorded on key teeth are low (8,9,14,15,44), even modest trait correlations may lead to overrepresented variation from traits that co-occur. Given the limitations of our study, the reportedx r utility estimates must be considered as minimum and not as exact estimates of the strength of correlation between neutral genetic and dental morphological variation.…”

“…In addition, trait frequencies are expected to be correlated with the level of trait expressivity within a population under a threshold model of quasicontinuous variation (57). Dental traits listed in the ASUDAS have little or no sexual dimorphism (14,15); therefore, it is a standard procedure to pool sexes (4,6,8,12). Population comparisons based on ASUDAS dental traits typically focus on key teeth (usually the most mesial member of a tooth district) because these are considered the most stable members in terms of development and evolution (15) and are largely independent from each other (8,9,14,15,44).…”

“…As a result, dental morphology is widely used for inferring the biogeographical origin of deceased individuals, particularly when no other biological markers are available. Typical applications in the study of dental morphology include ancestry identification of unknown individuals in forensic cases (1,2), the assessment of past population structure and history in archaeological contexts (3)(4)(5)(6)(7)(8)(9), and the reconstruction of hominin phylogenies in paleontological studies (10)(11)(12).…”

Through 40.000 Years of Human Presence in Southern Europe: The Italian Case Study

“…In addition to the Punics, the other main shapers of the Iron Age Sicilian genetic make-up were the Greeks, who established colonies on the island (and South Italy) starting from the 8 th century BCE [39]. According to recent findings, the Greek colonization was a more gradual and peaceful process than that described by ancient historians, characterized by greater interaction and close cohabitation between newcomers and local people [45]. This is probably the reason why modern southern Italians display a varying amount of Greek genetic influence [39], which could be described as a "Mediterranean continuum".…”

The Impact of dental wear on the analysis of morphological affinities based on dental non-metric traits

“…Dental nonmetric traits are assumed to lack significant sexual dimorphism, have minimal influence from divergent selection, and have high heritability (Irish et al, 2020;Scott & Irish, 2013;Scott & Turner II, 1997;Turner II et al, 1991). The required methods to analyze and quantify dental morphology are also cost efficient, and since teeth are often found in the archaeological record and highly resilient to taphonomic processes (Hillson, 2005), they are a good alternative to reconstruct population biological affinities and human mobility on individual , local Turner II & Scott, 1977), regional (Irish et al, 2017;Rathmann et al, 2019;Sutter, 2009;Turner II, 1976), and global scales (Hanihara, 2008;Scott & Irish, 2017;Scott & Turner II, 1997;Sutter, 2005). A prolific example of the latter can be seen in studies discussing the peopling of the Americas (Greenberg et al, 1986;Huffman, 2014;Powell, 1995Powell, , 1997Powell & Neves, 1998;Scott, Schmitz, et al, 2018;Stojanowski et al, 2013;Stojanowski & Johnson, 2015;Sutter, 2005;Turner II & Scott, 2013).…”