Genetic evidence and historical theories of the Asian and African origins of the present Malagasy population.

The origin of the Malagasy population has been a subject of speculation since the 16th century. Contributions of African, Asian, Indian, Melanesian, Arabic and Persian populations have been suggested based on physical and cultural anthropology, oral tradition, linguistics and later also by archaeology. In the mid-20th century, increased knowledge of heredity rules and technical progress enabled the identification of African and Asian populations as main contributors. Recent access to the genomic landscape of Madagascar demonstrated pronounced regional variability in the relative contributions of these two ancestries, yet with significant presence of both African and Asian components throughout Madagascar. This article reviews the extent to which genetic results have settled historical questions concerning the origin of the Malagasy population. After an overview of the early literature, the genetic results of the 20th and 21th centuries are discussed and then complemented by the latest results in genome-wide analyses. While there is still much uncertainty regarding when, how and the circumstances under which the ancestors of the modern Malagasy population arrived on the island, we propose a scenario based on historical texts and genomic results.

History of dental caries in Inuit populations: genetic implications and 'distance effect'.

Dental caries is considered the third most important scourge in the world. In North America, Inuit populations are the population the most severely affected by dental caries. It is often assumed that this situation can be explained by a combination of factors classical for Indigenous populations: remoteness (geographical distance), low economic status and low health literacy (cultural distance). Using a bibliographic approach, we tested this hypothesis of the "distance effect" by exploring the caries prevalence in other Indigenous populations living in high-income countries. Next, we tested whether the high prevalence of caries is due to population-specific characteristics by tracking caries prevalence over the past few centuries. In result, we showed that while other Indigenous populations are more impacted by caries than the general populations, the Inuit populations present the highest prevalence. Paradoxically, we showed also that past Inuit populations were almost immune to caries before 1950. These two elements suggest that the prevalence of caries observed presently is a recent maladaptation and that beyond the effect of cultural and geographical distance, specific biocultural factors have to be investigated.

The loss of biodiversity in Madagascar is contemporaneous with major demographic events.

Only 400 km off the coast of East Africa, the island of Madagascar is one of the last large land masses to have been colonized by humans. While many questions surround the human occupation of Madagascar, recent studies raise the question of human impact on endemic biodiversity and landscape transformation. Previous genetic and linguistic analyses have shown that the Malagasy population has emerged from an admixture that happened during the last millennium, between Bantu-speaking African populations and Austronesian-speaking Asian populations. By studying the sharing of chromosome segments between individuals (IBD determination), local ancestry information, and simulated genetic data, we inferred that the Malagasy ancestral Asian population was isolated for more than 1,000 years with an effective size of just a few hundred individuals. This isolation ended around 1,000 years before present (BP) by admixture with a small African population. Around the admixture time, there was a rapid demographic expansion due to intrinsic population growth of the newly admixed population, which coincides with extensive changes in Madagascar's landscape and the extinction of all endemic large-bodied vertebrates. Therefore, our approach can provide new insights into past human demography and associated impacts on ecosystems.

African Gene Flow Reduces Beta-Ionone Anosmia/Hyposmia Prevalence in Admixed Malagasy Populations.

While recent advances in genetics make it possible to follow the genetic exchanges between populations and their phenotypic consequences, the impact of the genetic exchanges on the sensory perception of populations has yet to be explored. From this perspective, the present study investigated the consequences of African gene flow on odor perception in a Malagasy population with a predominantly East Asian genetic background. To this end, we combined psychophysical tests with genotype data of 235 individuals who were asked to smell the odorant molecule beta-ionone (ßI). Results showed that in this population the ancestry of the OR5A1 gene significantly influences the ability to detect ßI. At the individual level, African ancestry significantly protects against specific anosmia/hyposmia due to the higher frequency of the functional gene (OR ratios = 14, CI: 1.8-110, p-value = 0.012). At the population level, African introgression decreased the prevalence of specific anosmia/hyposmia to this odorous compound. Taken together, these findings validate the conjecture that in addition to cultural exchanges, genetic transfer may also influence the sensory perception of the population in contact.

Smell and taste changes are early indicators of the COVID-19 pandemic and political decision effectiveness.

In response to the COVID-19 pandemic, many governments have taken drastic measures to avoid an overflow of intensive care units. Accurate metrics of disease spread are critical for the reopening strategies. Here, we show that self-reports of smell/taste changes are more closely associated with hospital overload and are earlier markers of the spread of infection of SARS-CoV-2 than current governmental indicators. We also report a decrease in self-reports of new onset smell/taste changes as early as 5 days after lockdown enforcement. Cross-country comparisons demonstrate that countries that adopted the most stringent lockdown measures had faster declines in new reports of smell/taste changes following lockdown than a country that adopted less stringent lockdown measures. We propose that an increase in the incidence of sudden smell and taste change in the general population may be used as an indicator of COVID-19 spread in the population.

Strong selection during the last millennium for African ancestry in the admixed population of Madagascar.

While admixed populations offer a unique opportunity to detect selection, the admixture in most of the studied populations occurred too recently to produce conclusive signals. By contrast, Malagasy populations originate from admixture between Asian and African populations that occurred ~27 generations ago, providing power to detect selection. We analyze local ancestry across the genomes of 700 Malagasy and identify a strong signal of recent positive selection, with an estimated selection coefficient >0.2. The selection is for African ancestry and affects 25% of chromosome 1, including the Duffy blood group gene. The null allele at this gene provides resistance to Plasmodium vivax malaria, and previous studies have suggested positive selection for this allele in the Malagasy population. This selection event also influences numerous other genes implicated in immunity, cardiovascular diseases, and asthma and decreases the Asian ancestry genome-wide by 10%, illustrating the role played by selection in recent human history.

Consenso Argentino de Cirugía Metabólica / ARGENTINE CONSENSUS ON METABOLIC SURGERY

Introducción: la creciente pandemia de obesidad y diabetes tipo 2 (DM2) demanda opciones terapéuticas más efectivas para lograr un adecuado control metabólico y disminuir la morbimortalidad cardiovascular en este grupo de pacientes. En este contexto, la cirugía metabólica (CM) constituye una herramienta innovadora, segura y eficaz que complementa pero no reemplaza a los cambios necesarios del estilo de vida y tratamiento médico. Objetivos: el objetivo del Consenso es la fundamentación y acuerdo de utilización de una técnica quirúrgica, específicamente el Bypass Gástrico en Y de Roux (BPGYR), en el tratamiento de pacientes con DM2 que presentan un índice de masa corporal (IMC) entre 30-35 kg/m2 e inadecuado control metabólico. Conclusiones: el Consenso Argentino de Cirugía Metabólica elaborado por la Sociedad Argentina de Diabetes (SAD), la Sociedad Argentina de Nutrición (SAN) y la Sociedad Argentina de Cirugía de la Obesidad (SACO) expresa la opinión de expertos sobre la evidencia científica disponible y propone considerar a la CM en el algoritmo terapéutico de pacientes con DM2 e IMC 30-35 kg/m2 que no logran adecuado control metabólico con tratamiento médico convencional. Se describen los criterios a tener en cuenta en la selección de pacientes para CM, y se destaca el rol del equipo multidisciplinario liderado por médicos especialistas en enfermedades endocrino-metabólicas en la selección, evaluación, preparación y seguimiento de estos pacientes.

Consenso Argentino de Cirugía Metabólica / Argentine Consensus on Metabolic Surgery

Introducción: la creciente pandemia de obesidad y diabetes tipo 2 (DM2) demanda opciones terapéuticas más efectivas para lograr un adecuado control metabólico y disminuir la morbimortalidad cardiovascular en este grupo de pacientes. En este contexto, la cirugía metabólica (CM) constituye una herramienta innovadora, segura y eficaz que complementa pero no reemplaza a los cambios necesarios del estilo de vida y tratamiento médico. Objetivos: el objetivo del Consenso es la fundamentación y acuerdo de utilización de una técnica quirúrgica, específicamente el Bypass Gástrico en Y de Roux (BPGYR), en el tratamiento de pacientes con DM2 que presentan un índice de masa corporal (IMC) entre 30-35 kg/m2 e inadecuado control metabólico. Conclusiones: el Consenso Argentino de Cirugía Metabólica elaborado por la Sociedad Argentina de Diabetes (SAD), la Sociedad Argentina de Nutrición (SAN) y la Sociedad Argentina de Cirugía de la Obesidad (SACO) expresa la opinión de expertos sobre la evidencia científica disponible y propone considerar a la CM en el algoritmo terapéutico de pacientes con DM2 e IMC 30-35 kg/m2 que no logran adecuado control metabólico con tratamiento médico convencional. Se describen los criterios a tener en cuenta en la selección de pacientes para CM, y se destaca el rol del equipo multidisciplinario liderado por médicos especialistas en enfermedades endocrino-metabólicas en la selección, evaluación, preparación y seguimiento de estos pacientes

Detección por parte de la familia de conductas que constituyen indicadores de riesgo para el desarrollo de trastornos de la conducta alimentaria en niños y adolescentes / Detection by the family of behaviors that are indicators of risk for developing eating disorders in children and adolescents

Objetivos: Identificar conductas, signos y otras variables que puedan ser observables por los familiares de los niños y adolescentes en riesgo de desarrollar Trastornos de la Conducta Alimentaria (TCA) como pautas de alarma, para tomar alguna conducta preventiva o intentar modificar patrones maladaptativos...