European Journal of Human Genetics (2005) 13, 902–912 & 2005 Nature Publishing Group All rights reserved 1018-4813/05 $30.00 www.nature.com/ejhg ARTICLE The population history of the Croatian linguistic minority of Molise (southern Italy): a maternal view Carla Babalini1,5, Cristina Martı´nez-Labarga1,5, Helle-Viivi Tolk2, Toomas Kivisild2, Rita Giampaolo1, Tiziana Tarsi1, Irene Contini1, Lovorka Barac´3, Branka Janic´ijevic´3, Irena Martinovic´ Klaric´3, Marijana Pericˇic´3, Anita Sujoldzˇic´3, Richard Villems2, Gianfranco Biondi4, Pavao Rudan3 and Olga Rickards*,1 1Department of Biology, University of Rome ‘Tor Vergata’, 00133 Rome, Italy; 2Department of Evolutionary Biology, University of Tartu, and Estonian Biocentre, 51010 Tartu, Estonia; 3Institute for Anthropological Research, 10000 Zagreb, Croatia; 4Department of Environmental Sciences, University of L’Aquila, 67010 L’Aquila, Italy This study examines the mitochondrial DNA (mtDNA) diversity of the Croatian-speaking minority of Molise and evaluates its potential genetic relatedness to the neighbouring Italian groups and the Croatian parental population. Intermatch, genetic distance, and admixture analyses highlighted the genetic similarity between the Croatians of Molise and the neighbouring Italian populations and demonstrated that the Croatian-Italian ethnic minority presents features lying between Croatians and Italians. This finding was confirmed by a phylogeographic approach, which revealed both the prevalence of Croatian and the penetrance of Italian maternal lineages in the Croatian community of Molise. These results suggest that there was no reproductive isolation between the two geographically proximate, yet culturally distinct populations living in Italy. The gene flow between the Croatian-Italians and the surrounding Italian populations indicate, therefore, that ethnic consciousness has not created reproductive barriers and that the Croatian-speaking minority of Molise does not represent a reproductively isolated entity. European Journal of Human Genetics (2005) 13, 902–912. doi:10.1038/sj.ejhg.5201439; published online 11 May 2005 Keywords: mtDNA; haplogroups; Croatian-Italians; Croatians; Italians Introduction and associating people with each other, thus providing the People constituting an ethnic community share character- main social tie1 that could influence the genetic structure istic cultural traits of language, religion, patterns of social of an ethnic group through marriage and reproduction. interaction and a feeling of unity and solidarity. While The spoken language can, in fact, act as a genetic and community members also believe that they share a cultural barrier, increasing the genetic variation and common origin and history, very often this is only a myth. divergence between populations. However, the construc- Many scholars maintain that language is an important if tion of ethnic identity does not necessarily involve not the strongest feature of ethnic identity. Language biological contributions. represents the natural way of thinking, communicating, Among the various groups speaking non-Italian lan- guages who have slowly penetrated Italy since prehistoric times, the Croatian-speaking community of Molise repre- *Correspondence: Professor O Rickards, Dipartimento di Biologia, Uni- 2 versita` di Roma ‘Tor Vergata’, Via della Ricerca Scientifica n. 1, 00133 sents the smallest ethnolinguistic minority. Roma, Italy. Tel: þ 39 06 72594347; Fax: þ 39 06 2023500; E-mail: [email protected] Historic background 5These two authors contributed equally to this work Received 11 June 2004; revised 24 March 2005; accepted 12 April 2005; Population contacts between the two coasts of the Adriatic published online 11 May 2005 have existed since prehistoric times. According to historic mtDNA polymorphisms in the Croatian-Italians C Babalini et al 903 data, the first migrations of Croatians into central-south- Materials and methods ern Italy began as early as the 10th century and continued The study was carried out on three groups of unrelated and up to the 15th century. Small groups and families crossed apparently healthy people with attested maternal geneal- the Adriatic and formed their own small colonies.3 In ogy. The first group consisted of 41 schoolchildren (age contrast with these sporadic migrations, more lasting range, 11–15 years) from the three villages belonging to visible traces were left by Croatian immigrants to southern the Croatian ethnolinguistic minority of Molise (Acquavi- Italy during the 15th and 16th centuries. At that time, the va Collecroce, Montemitro and San Felice del Molise); the Ottomans were advancing through the Balkan Peninsula to second comprised 199 individuals from central-southern the Adriatic, forcing many population groups to flee from Italy (52 from Lazio, 48 from Campania, 73 from Abruzzo/ the continental interior toward the Adriatic coast where Molise, and 26 from Puglia); the third group consisted of they resettled on the Middle and Southern Adriatic 96 individuals from four villages located on the Makarska (Dalmatian) islands, the Istrian peninsula to the northwest coast near the islands of Bracˇ and Hvar, from north-west to and in the southern regions of Italy across the Adriatic. south-east: Krilo Jesenice (35), Mimice (24), Zaostrog (13) According to historic sources, 15 Croatian communities and Zˇivogosˇc´e (24). In addition, 311 individuals chosen resettled in the region of Molise, with a total of 7000 to randomly from the parish registries of three Croatian 8000 inhabitants.4 Their number grew to over 15 000 and islands in the eastern Adriatic (Middle Dalmatian islands) then gradually declined partially due to assimilation with (105 from Bracˇ, 108 from Hvar, and 98 from Korcˇula7,8), for the Italian population. Today, their descendents (total: which HVS-I complete sequences and RFLP analyses were 2081 individuals5) live in the mountainous inland villages available, were also included. The Krk sample was not used of Acquaviva Collecroce, San Felice del Molise and for comparison since the ethnohistory of this island differs Montemitro. Although Croatian is still spoken in all three considerably from that of the other Croatian islands.7 villages, the number of individuals and families speaking Figure 1 shows all sampling localities in Italy and Croatia it has greatly decreased through economically moti- and the reconstruction of historic migration directions. vated migrations to other regions of Italy and overseas 2 countries. Sample preparation and DNA extraction Croatian ethnolinguistic minority of Italy Total gen- ome DNA was extracted from a small amount of blood samples according to the method described in Budowle Linguistic evidence of the origin of Croatian et al.9 The blood sample collection strategy is reported populations elsewhere.10 Throughout the last century, several different hypotheses as to the origin of these Croatian immigrants were put Populations of Central Italy After obtaining informed forth, along with a range of possible locations of origin consent, blood or mouth swab samples were collected at including Istria and northern Dalmatia or Middle Dalma- the Blood Transfusion Centre of the Hospital of Rome tia. However, a thorough linguistic analysis comparing the ‘Umberto I’. DNA was extracted following the procedures Molise speech with the local vernaculars of 52 villages in of Miller et al11 and Budowle et al.9 Istria and Dalmatia has shown that the speech of the inhabitants of Molise is undoubtedly a sˇtokavian-ikavian Populations of Croatia DNA extraction from blood dialect of the Croatian spoken in Middle Dalmatia before samples and mtDNA analyses were performed following the Turkish invasion.6 The linguistic analysis clearly the procedures reported in Tolk et al.7 supports the hypothesis that the ancestral homeland of the immigrants into the region of Molise is to be found in mtDNA analyses this area, specifically between the Cetina and Neretva D-loop PCR amplification and direct sequence analy- rivers. sis The mtDNA HVS-I and HVS-II of the Croatian–Italian The present study examines the genetic effects of and the Italian samples were amplified simultaneously by geographic and linguistic subdivision in Molise, a small applying the multiplex amplification strategy. For a region of Italy. In particular, direct sequencing of the two detailed description of PCR and automated sequencing most variable segments of the mitochondrial DNA conditions, see Rickards et al.12,13 (mtDNA) control region and high-resolution RFLP analysis The HVS-I was amplified and sequenced for the southern of the whole molecule were performed to describe mtDNA Croatian samples between the region at nps 16024 and variation in the Croatian minority of Molise, the Croatian 16400.14,15 parental population and the neighbouring Italian groups in order to assess whether the spoken language has RFLP screening RFLP screening was performed in a contributed to the preservation of the genetic identity of hierarchical manner. Purified DNA of selected Croatian- the Croatians living in Italy. Italian, Croatian and Italian samples was used to amplify European Journal of Human Genetics mtDNA polymorphisms in the Croatian-Italians C Babalini et al 904 Figure 1 Geographical map showing the location of the study samples and the migration routes from Croatia to Italy. the polymorphic sites defining Eurasian and African Haplogroup classification strategy For all the samples, mtDNA lineages.16 Primers and conditions are reported in