The genetic history of Italians: new-insights from uniparentally-inherited markers

Genetic differences among human groups can be ascribed both to the broad-scale extents of pre-historical and historical migrations and to the fine-scale impacts of socio-cultural and geographic heterogeneity. In this thesis, the genetic information provided by uniparental markers were exploited to address different aspects of the Italian population history, by combining macro- and micro-geographic investigations at different spatial and temporal scales. To firstly assess the overall Italian variability, Y-chromosome and mtDNA markers were deeply typed in ~900 individuals from continental Italy, Sicily and Sardinia. Sex-biased patterns and contrasting demographic histories were observed for males and females. Differential European and Mediterranean contributions were invoked to explain the paternal genetic sub-structure observed in peninsular Italy, compared to the homogeneous maternal genetic landscape. If Neolithic showed to be one principal determinant of the detected paternal structure, local insights into specific Italian regional contexts highlighted the importance of Post-Neolithic contributions. Among them, migrations from the Balkans (particularly Greece) during late Metal Ages, played a relevant role in the cultural and genetic transitions occurred in Sicily and Southern Italy. On a finer geographic and temporal perspective, the more recent layers of Italian genetic history and some aspects of the gene-culture interaction were assessed by exploring the genetic variability within two “marginal populations”: Arbereshe of Southern Italy and Partecipanza in Northern Italy. The Arbereshe are Albanian-speaking communities settled in Sicily and Calabria since the end of Middle Ages. Despite sharing common genetic and cultural backgrounds, these groups revealed diverging micro-evolutionary histories, implying different founding events and different patterns of cultural isolation and local admixture. Partecipanza is an idiosyncratic institution of Medieval origin aimed at sharing and devolving collective lands. This case-study exemplified that socio-economic stratification within the same population may induce sex-biased genetic structuring and the maintenance of otherwise hidden historical genetic traces.

Skeletal variability of the fibular ends and evolutionary implications

This thesis investigates the morphological variations of fibular extremities in humans and non-human hominids using a 3D Geometric Morphometric approach. The study has three objectives: (1) to assess the shape, form, and size variations of fibular epiphyses within the human species, highlighting sexually dimorphic features; (2) to explore interpopulation variability of fibular extremities from the Upper Paleolithic to the 20th century, comparing subsistence, mobility, and lifestyles; and (3) to examine interspecific variations in fibular ends, testing potential associations with locomotor and positional behavior among extant hominid taxa. In terms of intraspecific variations, sex-related differences in fibular form and size were observed, suggesting distinct functional requirements for the lower limb between sexes. Interpopulation variations revealed a decline in activity level over time, influenced by terrain and footwear use. Hunter-gatherer groups exhibited greater joint mobility, loading, and range of motion compared to sedentary pre- and post-industrial populations. Interspecific variations demonstrated significant morphological differences among hominid taxa, indicating functional implications related to both phylogeny and specific loading patterns on the lower limb. The study identified features indicative of bipedalism in humans, as well as shared characteristics among non-human great apes. Furthermore, distinguishing features were found between Asian and African apes, along with unique morphological signals associated with distinct positional behavior in each hominid taxa. By comprehensively analyzing fibular morphology, this research sheds light on the importance of this bone in knee support, ankle stabilization, and overall locomotor function. The findings contribute to our understanding of the evolutionary and functional aspects of the fibula across human populations and non-human hominids throughout history.