Xavier Roca-Rada

• PhD
• Postdoctoral Research Associate at Brown University

In many human rights and criminal contexts, skeletal remains are often the only available samples, and they present a significant challenge for forensic DNA profiling due to DNA degradation. Ancient DNA methods, particularly capture hybridization enrichment, have been proposed for dealing with severely degraded bones, given their capacity to yield...

Contamination with exogenous DNA presents a significant challenge in ancient DNA (aDNA) studies of single organisms. Failure to address contamination from microbes, reagents, and present-day sources can impact the interpretation of results. Although field and laboratory protocols exist to limit contamination, there is still a need to accurately dis...

Background Recent ancient DNA studies uncovering large-scale demographic events in Iberia have focused primarily on Spain, with limited reports for Portugal, a country located at the westernmost edge of continental Eurasia. Here, we introduce the largest collection of ancient Portuguese genomic datasets (n = 68) to date, spanning 5,000 years, from...

In-solution hybridisation enrichment of genetic markers is a method of choice in paleogenomic studies, where the DNA of interest is generally heavily fragmented and contaminated with environmental DNA, and where the retrieval of genetic data comparable between individuals is challenging. Here, we benchmarked the commercial "Twist Ancient DNA" reage...

In around 716 AD, the city of Santarém, Portugal, was conquered by the Berber and Arab armies that swept the Iberian Peninsula and went on to rule the region until the 12th century. Archaeological excavations in 2007/08 discovered an Islamic necropolis (Avenida 5 de Outubro #2–8) that appears to contain the remains of an early Muslim population in...

Aneuploidies, and in particular, trisomies represent the most common genetic aberrations observed in human genetics today. To explore the presence of trisomies in historic and prehistoric populations we screen nearly 10,000 ancient human individuals for the presence of three copies of any of the target autosomes. We find clear genetic evidence for...

Les récentes avancées en paléogénomique ont ouvert de nouvelles perspectives sur l’étude des pratiques funéraires et des structures sociales en Mésoamérique. Cette note présente les premiers résultats d’un programme en cours dans une petite résidence sur le site de Naachtun (Guatemala) numérotée 5N6. Les possibilités d’estimation du sexe offertes p...

In‐solution hybridisation enrichment of genetic variation is a valuable methodology in human paleogenomics. It allows enrichment of endogenous DNA by targeting genetic markers that are comparable between sequencing libraries. Many studies have used the 1240k reagent—which enriches 1,237,207 genome‐wide SNPs—since 2015, though access was restricted....

In-solution hybridisation enrichment of genetic variation is a valuable methodology in human paleogenomics. It allows enrichment of endogenous DNA by targeting genetic markers that are comparable between sequencing libraries. Many studies have used the 1240k reagent-which enriches 1,237,207 genome-wide SNPs-since 2015, though access was restricted....

Ancient DNA analysis of ancestral Mexicans reveals a complex demographic history.

The Southern Cone of South America (SCSA) is a key region for investigations about the peopling of the Americas. However, little is known about the eastern sector, the Argentinian Pampas. We analysed 18 mitochondrial genomes—7 of which are novel—from human skeletal remains from 3 Early to Late Holocene archaeological sites. The Pampas presents a di...

Mesoamerica is a historically and culturally defined geographic area comprising current central and south Mexico, Belize, Guatemala, El Salvador, and border regions of Honduras, western Nicaragua, and northwestern Costa Rica. The permanent settling of Mesoamerica was accompanied by the development of agriculture and pottery manufacturing (2500 BCE–...

Many of us are fascinated by narratives regarding the origin and evolution of our species. Who are we? How did we people the world? Answers to these simple questions remain elusive even though researchers have been quite successful in describing past human morphology and culture using evidence from anthropology, archaeology, history, sociology and...