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In this study, 123 unrelated Portuguese Gypsies were analyzed for 15 highly polymorphic autosomal short tandem repeats (STRs). Average gene diversity across the 15 markers was 76.7%, which is lower than that observed in the non-Gypsy Portuguese population. Subsets of STRs were used to perform comparisons with other Gypsy and corresponding host populations. Interestingly, diversity reduction in Gypsy groups compared to their non-Gypsy surrounding populations apparently varied according to an East-West gradient, 'which parallels their dispersion in Europe as well as a decrease in complexity of their internal structure. Analysis of genetic distances revealed that the average level of genetic differentiation between Gypsy groups was much larger than that observed between the corresponding non-Gypsy populations. The high rate of heterogeneity among Gypsies can be explained by strong genetic drift and limited intergroup gene flow. However, when genetic relationships were addressed through principal component analysis, all GSrpsy populations clustered together and was clearly distinguished from other populations, a pattern that suggests their common origin. Concerning the putative ancestral genetic component, admixture analysis did iot reveal strong Indian ancestry in the current Gypsy gene pools, in contrast to the high admixture estimates for either Europeans or Western Asians [ABSTRACT FROM AUTHOR]

The establishment of Jewish communities in the territory of contemporary Portugal is archaeologically documented since the 3rd century CE, but their settlement in Trás-os-Montes (NE Portugal) has not been proved before the 12th century. The Decree of Expulsion followed by the establishment of the Inquisition, both around the beginning of the 16th century, accounted for a significant exodus, as well as the establishment of crypto-Jewish communities. Previous Y chromosome studies have shown that different Jewish communities share a common origin in the Near East, although they can be quite heterogeneous as a consequence of genetic drift and different levels of admixture with their respective host populations. To characterize the genetic composition of the Portuguese Jewish communities from Trás-os-Montes, we have examined 57 unrelated Jewish males, with a high-resolution Y-chromosome typing strategy, comprising 16 STRs and 23 SNPs. A high lineage diversity was found, at both haplotype and haplogroup levels (98.74 and 82.83%, respectively), demonstrating the absence of either strong drift or founder, effects. A deeper and more detailed investigation is required to clarify how these communities avoided the expected inbreeding caused by over four centuries.of religious repression. Concerning haplogroup lineages, we detected some admixture with the Western European non-Jewish populations (R1b1b2-M269, ∼28%), along with a strong ancestral component reflecting their origin in the Middle East [J1(xJ1a-M267), ∼12%; J2-M172, ∼25%; T-M70, ∼16%] and in consequence Trás-os-Montes Jews were found to be more closely related with other Jewish groups, rather than with the Portuguese non-Jewish population. [ABSTRACT FROM AUTHOR]