Ancient genomes from a rural site in Imperial Rome (1st-3rd cent. CE): a genetic junction in the Roman Empire.

BACKGROUND: Rome became the prosperous Capital of the Roman Empire through the political and military conquests of neighbouring areas. People were able to move Romeward modifying the Rome area's demographic structure. However, the genomic evidence for the population of one of the broadest Empires in antiquity has been sparse until recently. AIM: The genomic analysis of people buried in Quarto Cappello del Prete (QCP) necropolis was carried out to help elucidate the genomic structure of Imperial Rome inhabitants. SUBJECTS AND METHODS: We recruited twenty-five individuals from QCP for ancient DNA analysis through whole-genome sequencing. Multiple investigations were carried out to unveil the genetic components featuring in the studied samples and the community's putative demographic structure. RESULTS: We generated reliable whole-genome data for 7 samples surviving quality controls. The distribution of Imperial Romans from QCP partly overlaps with present-day Southern Mediterranean and Southern-Near Eastern populations. CONCLUSION: The genomic legacy with the south-eastern shores of the Mediterranean Sea and the Central and Western Northern-African coast funerary influence pave the way for considering people buried in QCP as resembling a Punic-derived human group.

Uniparental Lineages from the Oldest Indigenous Population of Ecuador: The Tsachilas.

Together with Cayapas, the Tsachilas constitute the oldest population in the country of Ecuador and, according to some historians, they are the last descendants of the ancient Yumbos. Several anthropological issues underlie the interest towards this peculiar population: the uncertainty of their origin, their belonging to the Barbacoan linguistic family, which is still at the center of an intense linguistic debate, and the relations of their Yumbo ancestors with the Inca invaders who occupied their ancient territory. Our contribution to the knowledge of their complex past was the reconstruction of their genetic maternal and paternal inheritance through the sequencing of 70 entire mitochondrial genomes and the characterization of the non-recombinant region of the Y chromosome in 26 males. For both markers, we built comprehensive datasets of various populations from the surrounding geographical area, northwestern South America, NW, with a known linguistic affiliation, and we could then compare our sample against the overall variability to infer relationships with other Barbacoan people and with other NW natives. We found contrasting patterns of genetic diversity for the two markers, but generally, our results indicated a possible common origin between the Tsachilas, the Chachi, and other Ecuadorian and Colombian Barbacoans and are suggestive of an interesting ancient linkage to the Inca invaders in Yumbo country.

Dissecting the Pre-Columbian Genomic Ancestry of Native Americans along the Andes-Amazonia Divide.

Extensive European and African admixture coupled with loss of Amerindian lineages makes the reconstruction of pre-Columbian history of Native Americans based on present-day genomes extremely challenging. Still open questions remain about the dispersals that occurred throughout the continent after the initial peopling from the Beringia, especially concerning the number and dynamics of diffusions into South America. Indeed, if environmental and historical factors contributed to shape distinct gene pools in the Andes and Amazonia, the origins of this East-West genetic structure and the extension of further interactions between populations residing along this divide are still not well understood. To this end, we generated new high-resolution genome-wide data for 229 individuals representative of one Central and ten South Amerindian ethnic groups from Mexico, Peru, Bolivia, and Argentina. Low levels of European and African admixture in the sampled individuals allowed the application of fine-scale haplotype-based methods and demographic modeling approaches. These analyses revealed highly specific Native American genetic ancestries and great intragroup homogeneity, along with limited traces of gene flow mainly from the Andes into Peruvian Amazonians. Substantial amount of genetic drift differentially experienced by the considered populations underlined distinct patterns of recent inbreeding or prolonged isolation. Overall, our results support the hypothesis that all non-Andean South Americans are compatible with descending from a common lineage, while we found low support for common Mesoamerican ancestors of both Andeans and other South American groups. These findings suggest extensive back-migrations into Central America from non-Andean sources or conceal distinct peopling events into the Southern Continent.

Signs of continental ancestry in urban populations of Peru through autosomal STR loci and mitochondrial DNA typing.

The human genetic diversity around the world was studied through several high variable genetic markers. In South America the demic consequences of admixture events between Native people, European colonists and African slaves have been displayed by uniparental markers variability. The mitochondrial DNA (mtDNA) has been the most widely used genetic marker for studying American mixed populations, although nuclear markers, such as microsatellite loci (STRs) commonly used in forensic science, showed to be genetically and geographically structured. In this work, we analyzed DNA from buccal swab samples of 296 individuals across Peru: 156 Native Amazons (Ashaninka, Cashibo and Shipibo from Ucayali, Huambiza from Loreto and Moche from Lambayeque) and 140 urban Peruvians from Lima and other 33 urban areas. The aim was to evaluate, through STRs and mtDNA variability, recent migrations in urban Peruvian populations and to gain more information about their continental ancestry. STR data highlighted that most individuals (67%) of the urban Peruvian sample have a strong similarity to the Amazon Native population, whereas 22% have similarity to African populations and only ~1% to European populations. Also the maternally-transmitted mtDNA confirmed the strong Native contribution (~90% of Native American haplogroups) and the lower frequencies of African (~6%) and European (~3%) haplogroups. This study provides a detailed description of the urban Peruvian genetic structure and proposes forensic STRs as a useful tool for studying recent migrations, especially when coupled with mtDNA.