The search for a method that utilizes biological information to predict humans’ place of origin has occupied scientists for millennia. Over the past four decades, scientists have employed genetic data in an effort to achieve this goal but with limited success. While biogeographical algorithms using next-generation sequencing data have achieved an accuracy of 700 km in Europe, they were inaccurate elsewhere. Here we describe the Geographic Population Structure (GPS) algorithm and demonstrate its accuracy with three data sets using 40,000–130,000 SNPs. GPS placed 83% of worldwide individuals in their country of origin. Applied to over 200 Sardinians villagers, GPS placed a quarter of them in their villages and most of the rest within 50 km of their villages. GPS’s accuracy and power to infer the biogeography of worldwide individuals down to their country or, in some cases, village, of origin, underscores the promise of admixture-based methods for biogeography and has ramifications for genetic ancestry testing.

Taste sensitivity to PROP varies greatly among individuals and is associated with polymorphisms in the bitter receptor gene TAS2R38, and with differences in fungiform papilla density on the anterior tongue surface. Recently we showed that the PROP non-taster phenotype is strongly associated with the G variant of polymorphism rs2274333 (A/G) of the gene that controls the salivary trophic factor, gustin. The aims of this study were 1) to investigate the role of gustin gene polymorphism rs2274333 (A/G), in PROP sensitivity and fungiform papilla density and morphology, and 2) to investigate the effect of this gustin gene polymorphism on cell proliferation and metabolic activity. Sixty-four subjects were genotyped for both genes by PCR techniques, their PROP sensitivity was assessed by scaling and threshold methods, and their fungiform papilla density, diameter and morphology were determined. In vitro experiments examined cell proliferation and metabolic activity, following treatment with saliva of individuals with and without the gustin gene mutation, and with isolated protein, in the two iso-forms. Gustin and TAS2R38 genotypes were associated with PROP threshold (p=0.0001 and p=0.0042), but bitterness intensity was mostly determined by TAS2R38 genotypes (p<0.000001). Fungiform papillae densities were associated with both genotypes (p<0.014) (with a stronger effect for gustin; p=0.0006), but papilla morphology was a function of gustin alone (p<0.0012). Treatment of isolated cells with saliva from individuals with the AA form of gustin or direct application of the active iso-form of gustin protein increased cell proliferation and metabolic activity (p<0.0135). These novel findings suggest that the rs2274333 polymorphism of the gustin gene affects PROP sensitivity by acting on fungiform papilla development and maintenance, and could provide the first mechanistic explanation for why PROP super-tasters are more responsive to a broad range of oral stimuli.

These data showed that responsiveness to PROP is inversely related to BMI and salivary ionic zinc concentrations. The gustin gene dimorphism rs2274333 observed in supertaster and nontaster subjects may influence the protein conformation and, thereby, affect zinc ion binding. Our data showed a direct association between PROP sensitivity and a polymorphism in the gustin gene that is hypothesized to affect its function. This trial was registered at clinicaltrials.gov as UNICADBSITB-1.

We generated genome-wide ancient DNA data from the Balearic Islands, Sicily, and Sardinia, increasing the number of individuals with reported data from 5 to 66. The oldest individual from the Balearic Islands (~2400 BCE) carried ancestry from Steppe pastoralists that likely derived from west-to-east migration from Iberia, while two later Balearic individuals had less. In Sicily, Steppe pastoralist ancestry arrived by ~2200 BCE in part from Iberia; Iranian-related ancestry arrived by the mid-second millennium BCE contemporary to its previously documented spread to the Aegean; and there was large-scale population replacement following the Bronze Age. In Sardinia, nearly all ancestry derived from the island’s early farmers until the first millennium BCE, with an exception of a third millennium BCE outlier who had primarily North African ancestry and who along with an approximately contemporary Iberian documents widespread Africa-to-Europe gene flow in the Chalcolithic. Major immigration into Sardinia began in the first millennium BCE and today no more than 56–62% of Sardinian ancestry is from its first farmers, which is lower than previous estimates highlighting how Sardinia—like every other region in Europe—has been a stage for major movement and mixtures of people.