Carla Babalini

The population history of the Croatian linguistic minority of Molise (southern Italy): a maternal view.

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.

Polymorphisms of the COL1A2, CYP1A1 and HS1,2 Ig enhancer genes in the Tuaregs from Libya

Background: Restriction fragment length polymorphisms (RFLPs) of the COL1A2 and CYP1A1 and short tandem repeats of HS1,2 Ig enhancer genes are proving to be useful markers for describing human populations and thus are of interest for anthropogenetic research. Moreover, they can provide useful information in identifying alleles and haplotypes associated with particular forms of common diseases or for pharmacogenomics studies. Aim: The objective of this study was to define the genetic structure of Libyan Tuaregs and to establish the degree of genetic homogeneity amongst the El Awaynat and Tahala groups. Subjects and methods: Tuareg individuals from El Awaynat (n = 99) and Tahala (n = 18), in Libyan Sahara, were analysed for the RFLPs of COL1A2 and CYP1A1 and short tandem repeats of HS1,2 Ig enhancer genes. In order to provide a clearer picture of COL1A2, CYP1A1 and HS1,2 Ig enhancer allele and haplotype frequency distributions in various human groups distributed over a wide geographic area, comparisons with other African, European and Asian populations were carried out by analysis of molecular variance (AMOVA) and genetic distance analysis. Results: No significant level of differentiation was evident between the two Libyan Tuareg groups according to AMOVA. For the CYP1A1 gene, a possible new haplotype was observed, even though at a very low frequency. Linkage disequilibrium was assessed only for COL1A2, since CYP1A1 turned out to be poorly polymorphic for m2 and m3. Conclusions: Statistical analyses showed that Tuaregs from Libya are located in a intermediate position between south Saharan populations on one side and the Europeans and the Asians on the other.

Restriction Fragment Length Polymorphisms of Type I Collagen Locus 2 (COL1A2) in Two Communities of African Ancestry and Other Mixed Populations of Northwestern Ecuador

Restriction fragment length polymorphisms are good anthropological markers for discriminating geographically distinct populations at both the allele and the haplotype level. Two communities of African ancestry and ladinos, mestizos, and mulattoes living in the Esmeraldas province in northwestern Ecuador were analyzed for three RFLPs (EcoRI, RsaI, and MspI) of the COL1A2 gene. Also, the same markers were studied in a population sample from Spain to compare the allele and haplotype frequencies of the Esmeraldas populations with those of their representative European parental population. Data for the native American and sub-Saharan African founder components were available from the literature. No significant levels of differentiation between the two African Ecuadoran communities emerged from either the frequency analysis of each single marker and all three RFLP markers together or from the AMOVA. The ladinos and mestizos also showed a rather similar distribution of allele and haplotype frequencies, confirming that the two ethnic terms do not correspond to genetically different populations. The comparison with the supposed founding European, sub-Saharan African, and native American populations indicated a large presence of African genes in the gene pool of both communities, with a higher proportion of the Amerindian component in Viche than in Rio Cayapas. The present findings confirm the previous genetic admixture estimates based on nuclear and mitochondrial DNA markers and the demographic data.

COL1A2 (type I collagen) polymorphisms in the Colorado Indians of Ecuador.

Background: EcoRI, MspI and RsaI restriction fragment length polymorphisms (RFLPs) of the COL1A2 (type I collagen) gene are proving to be extremely informative markers for describing human populations; therefore they hold considerable potential for anthropogenetic research. Aim: The objective of this study was to characterize at the DNA level the Colorado Indians from Ecuador, for whom only blood group frequency information is available, and to investigate their relationships with the Cayapa—another Ecuadoran Native American group belonging to the same linguistic affiliation—and other world populations. Subjects and methods: Colorado Indians (n = 80) were analysed for the three anthropologically informative RFLPs of the COL1A2 gene. To better define the genetic relationship between this group and other populations, principal component analysis (PCA) was performed and genetic distances were estimated. Population genetic structure was tested through analysis of molecular variance (AMOVA) by comparing haplotype frequencies. Results: COL1A2 allele and haplotype frequencies showed a certain degree of heterogeneity between the two Chibchan populations of Ecuador. The AMOVA test detected a significant level of differentiation (Fst = 0.034, p = 0.0049) between Colorado and Cayapa Indians. PC and genetic distance analyses showed a clear-cut separation between African and non-African populations; within the latter, the two Native American groups were differentiated from each other. Conclusions: The present findings suggest the presence of a low level of genetic relatedness between the Colorado and the Cayapa, despite their supposed common ethnogenesis. This confirms what has been inferred from other genetic data about the high degree of heterogeneity among Native Americans, even within the same linguistic branch, thus supporting the existence of genetic sub-structure within the central and southern American populations. Résumé. Arrière plan: Les polymorphismes de longueurs de fragments de restriction (RFLP) du gène COL1A2 (collagène de type 1) apparaissent comme des marqueurs humains extrêmement informatifs; ils présentent donc un intérêt potentiel considérable pour les recherches d’anthropogénétique. But: Cette étude caractérise le niveau d’ADN des indiens Colorado de l’Equateur, pour lesquels est seulement disponible l’information sur les fréquences des groupes sanguins, et examine leur relation avec un autre groupe amérindien d’Equateur de même affiliation linguistique, les indiens Cayapa, ainsi qu’avec d’autres populations. Sujets et méthodes: 80 indiens Colorado ont été analysés par rapport aux trois RFLP du gène COL1A2 anthropologiquement informatifs. Afin de mieux définir les relations génétiques de ce groupe avec d’autres populations, on a effectué une analyse en composantes principales et estimé des distances génétiques. La structure génétique de la population a été éprouvée par analyse de variance moléculaire (AMOVA) en comparant les fréquences haplotypiques. Résultats: L’allèle COLA12 et les fréquences haplotypiques indiquent un certain degré d’hétérogénéité des deux populations Chibchan d’Equateur. Le test AMOVA détecte un niveau significatif de différenciation (Fst = 0,034 p = 0.0049) entre indiens Colorado et Cayapa. Les analyses de CP et de distances génétiques montrent une séparation nette entre populations africaines et non africaines. Parmi ces dernières, les deux groupes amérindiens se séparent l’un de l’autre. Conclusion: Ces résultats suggèrent une relation génétique faible entre Colorado et Cayapa, en dépit de leur ethnogenèse supposée commune. Ils confirment ce qui a été inféré à partir d’autres données génétiques, concernant le haut degré d’hétérogénéité des amérindiens, même au sein d’une même branche linguistique, ce qui soutient l’hypothèse de l’existence d’une sous structure génétique dans les populations amérindiennes du centre et du sud des continents américains. Zusammenfassung. Hintergrund: EcoRI-, MspI- und RsaI-Restriktionsfragmentlängen-Polymorphismen (restriction fragment length polymorphisms, RFLPs) des COL1A2-(Typ I-Kollagen)-Gens erweisen sich als besonders informative Marker, um menschliche Populationen zu beschreiben; dadurch haben sie ein beträchtliches Potenzial für anthropogenetische Untersuchungen. Ziel: Das Ziel dieser Studie war, Colorado-Indianer aus Ecuador, für die nur Information betreffend Blutgruppenhäufigkeit vorhanden ist, auf DNS-Ebene zu charakterisieren und ihre Beziehung mit den Cayapa – einer anderen eingeborenen Amerikanischen Bevölkerung Ecuadors, die miteinander sprachlich verwandt sind – und anderen Populationen dieser Welt zu untersuchen. Probanden und Methoden: Colorado-Indianer (n = 80) wurden betreffend drei anthropologisch informative RFLPs des COL1A2-Gens untersucht. Um die genetische Beziehung zwischen dieser Gruppe und anderen Populationen besser definieren zu können, wurden Hauptkomponenten-Analysen (principal component analysis, PCA) gerechnet und genetische Distanzen bestimmt. Die genetische Struktur der Population wurde mittels einer Analyse der molekularen Varianz (analysis of molecular variance, AMOVA) durch Vergleich von Haplotyp-Häufigkeiten getestet. Ergebnisse: COL1A2-Allel- und Haplotyp-Häufigkeiten zeigten ein gewisses Maß an Heterogenität zwischen den beiden Chibchan Populationen aus Ecuador. Der AMOVA-Test zeigte einen signifikanten Unterschied (Fst = 0,034, p = 0,0049) zwischen Colorado- und Cayapa-Indianern. Hauptkomponenten-Analysen und die Analyse der genetischen Distanz zeigten eine klare Trennung zwischen Afrikanern und nicht-Afrikanischen Populationen; bei den letzteren ließen sich die beiden eingeborenen Amerikanischen Populationen voneinander unterscheiden. Zusammenfassung: Die vorliegenden Ergebnisse legen nahe, dass zwischen den Colorado und den Cayapa, trotz ihres bisher vermuteten gemeinsamen ethnischen Ursprungs, nur ein niedriges Ausmaß an genetischer Verwandtschaft besteht. Das bestätigt, was schon aus anderen genetischen Untersuchungsbefunden über den hohen Grad an Heterogenität unter eingeborenen Amerikanischen Völkern – selbst innerhalb derselben Sprachenfamilie – geschlossen worden ist, und bestätigt damit das Vorhandensein von genetischen Unterstrukturen bei Mittel- und Südamerikanischen Völkern. Resumen. Antecedentes: Se ha comprobado que los polimorfismos de longitud de los fragmentos de restricción (RFLPs) EcoRI, MspI y RsaI, son marcadores muy informativos para describir a las poblaciones humanas; por tanto, tienen un potencial considerable para la investigación antropogenética. Objetivos: El objetivo de este estudio fue caracterizar a nivel del ADN a los indios Colorado de Ecuador, de los que solo se dispone de información sobre las frecuencias de grupos sanguíneos, e investigar sus relaciones con los Cayapa, otro grupo Americano nativo de Ecuador que pertenece al mismo grupo lingüístico, y con otras poblaciones mundiales. Sujetos y métodos: Se analizaron indios Colorado (n = 80) para los tres RFLPs del gen COL1A2, antropológicamente informativos. Para definir mejor la relación genética entre este grupo y otras poblaciones, se realizó un análisis en componentes principales (ACP) y se estimaron las distancias genéticas. La estructura genética de la población se comprobó mediante un análisis molecular de la varianza (AMOVA) comparando frecuencias de haplotipos. Resultados: El alelo COL1A2 y las frecuencias haplotípicas mostraron un cierto grado de heterogeneidad entre las dos poblaciones Chibchan de Ecuador. El test AMOVA detectó un nivel de diferenciación significativo (Fst = 0,034, p = 0,0049) entre los indios Colorado y Cayapa. Los análisis PC y de distancia genética mostraron una separación neta entre las poblaciones Africanas y no Africanas; dentro de estas últimas, los análisis diferenciaron a los dos grupos Americanos nativos. Conclusión: Los resultados actuales sugieren la presencia de un bajo nivel de relación genética entre los indios Colorado y los Cayapa, a pesar de su supuesta etnogénesis común. Esto confirma lo ya inferido a partir de otros datos genéticos sobre el elevado grado de heterogeneidad entre los Americanos nativos, incluso dentro de la misma rama lingüística, y apoya la existencia de una subestructura genética dentro de las poblaciones centroamericanas y sudamericanas.