Autosomal Microsatellite and mtDNA Genetic Analysis in Sicily (Italy)

Dipartimento di Biopatologia e Metodologie Biomediche, Università di Palermo, Via Divisi 83, Palermo, Italy.
Annals of Human Genetics (Impact Factor: 2.21). 02/2003; 67(Pt 1):42-53. DOI: 10.1046/j.1469-1809.2003.00007.x
Source: PubMed


DNA samples from 465 blood donors living in 7 towns of Sicily, the largest island of Italy, have been collected according to well defined criteria, and their genetic heterogeneity tested on the basis of 9 autosomal microsatellite and mitochondrial DNA polymorphisms for a total of 85 microsatellite allele and 10 mtDNA haplogroup frequencies. A preliminary account of the results shows that: a) the samples are genetically heterogeneous; b) the first principal coordinates of the samples are correlated more with their longitude than with their latitude, and this result is even more remarkable when one outlier sample (Butera) is not considered; c) distances among samples calculated from allele and haplogroup frequencies and from the isonymy matrix are weakly correlated (r = 0.43, P = 0.06) but such correlation disappears (r = 0.16) if the mtDNA haplogroups alone are taken into account; d) mtDNA haplogroups and microsatellite distances suggest settlements of people occurred at different times: divergence times inferred from microsatellite data seem to describe a genetic composition of the town of Sciacca mainly derived from settlements after the Roman conquest of Sicily (First Punic war, 246 BC), while all other divergence times take root from the second to the first millennium BC, and therefore seem to backdate to the pre-Hellenistic period.
A more reliable association of these diachronic genetic strata to different historical populations (e.g. Sicani, Elymi, Siculi), if possible, must be postponed to the analysis of more samples and hopefully more informative uniparental DNA markers such as the recently available DHPLC-SNP polymorphisms of the Y chromosome.

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Available from: Giuseppe Matullo, Sep 29, 2014
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    • "In contrast with previous investigations on the distribution pattern of genetic variation in Sicily [7]–[8], our results point to a substantially homogeneous composition of maternal and paternal genetic pools both within Sicily (East vs. West) as well as between Sicily and Southern Italy (Table S4). The absence of significant differences in the distribution of HG frequencies along the east-west axis of the island, as observed not only among our Sicilian populations, but also when including the samples from Di Gaetano et al. (2009) [8], provides further support to these conclusions. "
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    ABSTRACT: Due to their strategic geographic location between three different continents, Sicily and Southern Italy have long represented a major Mediterranean crossroad where different peoples and cultures came together over time. However, its multi-layered history of migration pathways and cultural exchanges, has made the reconstruction of its genetic history and population structure extremely controversial and widely debated. To address this debate, we surveyed the genetic variability of 326 accurately selected individuals from 8 different provinces of Sicily and Southern Italy, through a comprehensive evaluation of both Y-chromosome and mtDNA genomes. The main goal was to investigate the structuring of maternal and paternal genetic pools within Sicily and Southern Italy, and to examine their degrees of interaction with other Mediterranean populations. Our findings show high levels of within-population variability, coupled with the lack of significant genetic sub-structures both within Sicily, as well as between Sicily and Southern Italy. When Sicilian and Southern Italian populations were contextualized within the Euro-Mediterranean genetic space, we observed different historical dynamics for maternal and paternal inheritances. Y-chromosome results highlight a significant genetic differentiation between the North-Western and South-Eastern part of the Mediterranean, the Italian Peninsula occupying an intermediate position therein. In particular, Sicily and Southern Italy reveal a shared paternal genetic background with the Balkan Peninsula and the time estimates of main Y-chromosome lineages signal paternal genetic traces of Neolithic and post-Neolithic migration events. On the contrary, despite showing some correspondence with its paternal counterpart, mtDNA reveals a substantially homogeneous genetic landscape, which may reflect older population events or different demographic dynamics between males and females. Overall, both uniparental genetic structures and TMRCA estimates confirm the role of Sicily and Southern Italy as an ancient Mediterranean melting pot for genes and cultures.
    Full-text · Article · Apr 2014 · PLoS ONE
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    • "In view of their heterogeneous background, the subject of genetic relationships between populations on the island of Sicily is controversial. Some studies based on classical polymorphisms, and later on autosomal DNA markers (Calò et al. 2003; Ghiani et al. 2002; Piazza et al. 1988; Romano et al. 2003), indicated that Sicily is genetically heterogeneous, with a considerable East–West gradient compatible with population settlements occurring at different times. Other authors (Rickards et al. 1998) state that there was no clear geographic clustering within Sicily, rejecting an East–West differentiation. "
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    ABSTRACT: The islands of the West Mediterranean have played a central role in numerous archaeological, historical and anthropological studies due to their active participation in the history of main Mediterranean civilisations. However, genetic data failed to fit in both their degree of internal differentiation and relationships. A set of 18 Alu markers and three short tandem repeats (STRs) closely linked to the CD4, F13B and DM Alu have been analysed in seven samples from Majorca, Corsica, Sardinia and Sicily to explore some of these issues. Our samples show a high genetic heterogeneity inside and among islands for the Alu data. Global differentiation among islands (F(ST) 2.2%) is slightly higher than that described for Europeans and North Africans. Both the estimated divergence times among samples and the high population heterogeneity revealed by Alu data are compatible with population differences since the first islands' settlement in the Paleolithic period. However, the high within-population diversities and the remarkable homogeneity observed in both STR and Alu/STR haplotype variation indicated that, at least since Neolithic times, gene flow has been acting in west Mediterranean. Genetic drift in west-coast Sardinia and gene flow in west Sicily have contributed to their general differentiation, whereas Corsica, Majorca and east Sicily seem to reflect more recent historical relationships from continental south Europe.
    Full-text · Article · Feb 2007 · Journal of Human Genetics
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    • "Geographic origin of populations genotyped in this study is indicated in Figure 1. The Sicilians, a subset of Sardinians and Tunisian sample origins have already been described (Romano et al. 2003; Ciminelli et al. 1995; Comas et al. 2000; Plaza et al. 2003). Sample sizes are as in Table 1. "
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    ABSTRACT: The Mediterranean region has been characterised by a number of pre-historical and historical demographic events whose legacy on the current genetic landscape is still a matter of debate. In order to investigate the degree of population structure across the Mediterranean, we have investigated Y chromosome variation in a large dataset of Mediterranean populations, 11 of which are first described here. Our analyses identify four main clusters in the Mediterranean that can be labelled as North Africa, Arab, Central-East and West Mediterranean. In particular, Near Eastern samples tend to separate according to the presence of Arab Y chromosome lineages, suggesting that the Arab expansion played a major role in shaping the current genetic structuring within the Fertile Crescent.
    Full-text · Article · Apr 2006 · Annals of Human Genetics
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