Human population genomics of the Western Mediterranean

This work explores the genetic landscape of the Western Mediterranean basin. Genome-wide data have been used in order to describe the genetics of the Island of Ibiza and France. In the first case, we found Ibiza being isolated from the other Spanish groups and linked this finding to genetic drift and inbreeding, also excluding any connection with the ancient Phoenician colonists often identified as direct ancestors of the islanders. Regarding France, we used sophisticated haplotype-based methods to disentangle the genetic landscape of this understudied European country and presented the first genetic picture of this population.Este trabajo explora el panorama genético presente en la cuenca del Mediterráneo Occidental. Se han utilizado datos de todo el genoma para describir la genética de la isla de Ibiza y Francia. En el primer caso, encontramos a Ibiza asilada del resto de grupos españoles y relacionamos este descubrimiento con el efecto de la deriva génica y la endogamia, excluyendo también cualquier conexión con los antiguos colonos Fenicios habitualmente identificados como ancestros directos de los isleños. Con respecto a Francia, usamos métodos sofisticados basados en haplotipos para describir el paisaje genético de este país europeo poco estudiado hasta la fecha, presentando la primera imagen genética de su población

Human population genomics of the Western Mediterranean

This work explores the genetic landscape of the Western Mediterranean basin. Genome-wide data have been used in order to describe the genetics of the Island of Ibiza and France. In the first case, we found Ibiza being isolated from the other Spanish groups and linked this finding to genetic drift and inbreeding, also excluding any connection with the ancient Phoenician colonists often identified as direct ancestors of the islanders. Regarding France, we used sophisticated haplotype-based methods to disentangle the genetic landscape of this understudied European country and presented the first genetic picture of this population.Este trabajo explora el panorama genético presente en la cuenca del Mediterráneo Occidental. Se han utilizado datos de todo el genoma para describir la genética de la isla de Ibiza y Francia. En el primer caso, encontramos a Ibiza asilada del resto de grupos españoles y relacionamos este descubrimiento con el efecto de la deriva génica y la endogamia, excluyendo también cualquier conexión con los antiguos colonos Fenicios habitualmente identificados como ancestros directos de los isleños. Con respecto a Francia, usamos métodos sofisticados basados en haplotipos para describir el paisaje genético de este país europeo poco estudiado hasta la fecha, presentando la primera imagen genética de su población

People from Ibiza: an unexpected isolate in the Western Mediterranean

In this study, we seek to understand and to correlate the genetic patterns observed in the population of the island of Ibiza in the Western Mediterranean basin with past events. Genome-wide genotypes of 189 samples representing 13 of 17 regions in Spain have been analyzed, in addition to 105 samples from the Levant, 157 samples from North Africa, and one ancient sample from the Phoenician Cas Molí site in Ibiza. Before the Catalans conquered the island in 1235 CE, Ibiza (Eivissa) had already been influenced by several cultures, starting with the Phoenicians, then the Carthaginians, followed by the Umayyads. The impact of these various cultures on the genetic structure of the islanders is still unexplored. Our results show a clear distinction between Ibiza and the rest of Spain. To investigate whether this was due to the Phoenician colonization or to more recent events, we compared the genomes of current Ibizans to that of an ancient Phoenician sample from Ibiza and to both modern Levantine and North African genomes. We did not identify any trace of Phoenician ancestry in the current Ibizans. Interestingly, the analysis of runs of homozygosity and changes in the effective population size through time support the idea that drift has shaped the genetic structure of current Ibizans. In addition to the small carrying capacity of the island, Ibiza experienced a series of dramatic demographic changes due to several instances of famine, war, malaria and plague that could have significantly contributed to its current genetic differentiation.Funding was provided by the Agencia Estatal de Investigación and Fondo Europeo de Desarollo Regional (FEDER) (grant CGL2016-75389-P), Agència de Gestió d’Ajuts Universitaris i de la Recerca (Generalitat de Catalunya) grant 2014 SGR 866, and “Unidad de Excelencia María de Maeztu”, funded by the MINECO (ref: MDM-2014-0370). SAB was supported by the Agencia Estatal de Investigación FPI grant BES-2014-06922

Exploring adaptive phenotypes for the human calcium-sensing receptor polymorphism R990G

Rainforest hunter-gatherers from Southeast Asia are characterized by specific morphological features including a particularly dark skin color (D), short stature (S), woolly hair (W), and the presence of steatopygia (S)-fat accumulation localized in the hips (DSWS phenotype). Based on previous evidence in the Andamanese population, we first characterized signatures of adaptive natural selection around the calcium-sensing receptor gene in Southeast Asian rainforest groups presenting the DSWS phenotype and identified the R990G substitution (rs1042636) as a putative adaptive variant for experimental follow-up. Although the calcium-sensing receptor has a critical role in calcium homeostasis by directly regulating the parathyroid hormone secretion, it is expressed in different tissues and has been described to be involved in many biological functions. Previous works have also characterized the R990G substitution as an activating polymorphism of the calcium-sensing receptor associated with hypocalcemia. Therefore, we generated a knock-in mouse for this substitution and investigated organismal phenotypes that could have become adaptive in rainforest hunter-gatherers from Southeast Asia. Interestingly, we found that mouse homozygous for the derived allele show not only lower serum calcium concentration but also greater body weight and fat accumulation, probably because of enhanced preadipocyte differentiation and lipolysis impairment resulting from the calcium-sensing receptor activation mediated by R990G. We speculate that such differential features in humans could have facilitated the survival of hunter-gatherer groups during periods of nutritional stress in the challenging conditions of the Southeast Asian tropical rainforests.This work was supported by Agencia Estatal de Investigación (AEI, DOI: 10.13039/501100011033), Fondo Europeo de Desarrollo Regional, Ministerio de Ciencia e Innovación, and Ministerio de Ciencia, Innovación y Universidades with project grants BFU2016-77961-P, PID2019-110933GB-I00, and the Unidad de Excelencia María de Maeztu Ref. CEX2018-000792-M; and by Agència de Gestió d'Ajuts Universitaris i de la Recerca, Generalitat de Catalunya (2017SGR00702). B.S. was supported with an FPI-MINECO PhD fellowship (BES-2017-080343). S.A. was supported by Beatriu de Pinós 2017 BP 00176 and by the Serra Hunter Fellowship from Generalitat de Catalunya