Previous genetic, anthropological and linguistic studies have shown that Roma (Gypsies) constitute a founder population dispersed throughout Europe whose origins might be traced to the Indian subcontinent. Linguistic and anthropological evidence point to Indo-Aryan ethnic groups from North-western India as the ancestral parental population of Roma. Recently, a strong genetic hint supporting this theory came from a study of a private mutation causing primary congenital glaucoma. In the present study, complete mitochondrial control sequences of Iberian Roma and previously published maternal lineages of other European Roma were analyzed in order to establish the genetic affinities among Roma groups, determine the degree of admixture with neighbouring populations, infer the migration routes followed since the first arrival to Europe, and survey the origin of Roma within the Indian subcontinent. Our results show that the maternal lineage composition in the Roma groups follows a pattern of different migration routes, with several founder effects, and low effective population sizes along their dispersal. Our data allowed the confirmation of a North/West migration route shared by Polish, Lithuanian and Iberian Roma. Additionally, eleven Roma founder lineages were identified and degrees of admixture with host populations were estimated. Finally, the comparison with an extensive database of Indian sequences allowed us to identify the Punjab state, in North-western India, as the putative ancestral homeland of the European Roma, in agreement with previous linguistic and anthropological studies.

Taste perception is crucial in monitoring food intake and, hence, is thought to play a significant role in human evolution. To gain insights into possible adaptive signatures in genes encoding bitter, sweet, and umami taste receptors, we surveyed the available sequence variation data from the 1000 Genomes Project Phase 3 for TAS1R (TAS1R1-3) and TAS2R (TAS2R16 and TAS2R38) families. Our study demonstrated that genes from these two families have experienced contrasting evolutionary histories: While TAS1R1 and TAS1R3 showed worldwide evidence of positive selection, probably correlated with improved umami and sweet perception, the patterns of variation displayed by TAS2R16 and TAS2R38 were more consistent with scenarios of balancing selection that possibly conferred a heterozygous advantage associated with better capacity to perceive a wide range of bitter compounds. In TAS2R16, such adaptive events appear to have occurred restrictively in mainland Africa, whereas the strongest evidence in TAS2R38 was detected in Europe. Despite plausible associations between taste perception and the TAS1R and TAS2R selective signatures, we cannot discount other biological mechanisms as driving the evolutionary trajectories of those TAS1R and TAS2R members, especially given recent findings of taste receptors behaving as the products of pleiotropic genes involved in many functions outside the gustatory system.

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 Gypsy 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 not reveal strong Indian ancestry in the current Gypsy gene pools, in contrast to the high admixture estimates for either Europeans or Western Asians.