Papers by Giovanni Poletti
upch.edu.pe
Page 1. Rev Neuropsiquiatria 71(1-4), 2008 65 Investigación en Salud Mental en América Latina y e... more Page 1. Rev Neuropsiquiatria 71(1-4), 2008 65 Investigación en Salud Mental en América Latina y el Caribe. Investigación en Salud Mental en América Latina y el Caribe: Enfoque en las Ciencias Básicas. Mental Health Research ...
Revista Brasileira de Psiquiatria, 2008
OBJECTIVE: The World Health Organization Atlas Project identified important deficiencies in world... more OBJECTIVE: The World Health Organization Atlas Project identified important deficiencies in world mental and neurological health resources. These deficiencies, especially evident in low and middle-income countries, can be overcome by improving research capacity. The objective of this study is to assess the status of mental and neurological research in Latin American countries and identify the main difficulties encountered in conducting research, publishing results, and shaping health policies, interventions, and programs. METHOD: Semi-structured interviews were conducted with 34 key informants from 13 Latin American countries. RESULTS: Participants reported that production of mental and neurological research in Latin American countries is low. Lack of financial and human resources, including lack of support from government agencies, were identified as the main factors contributing to the dearth of local research. The few research projects that do take place in Latin American countri...
BMC Public Health, 2009
Background: Research evidence is essential to inform policies, interventions and programs, and ye... more Background: Research evidence is essential to inform policies, interventions and programs, and yet research activities in mental and neurological (MN) health have been largely neglected, particularly in low-and middle-income countries.
PLoS Genetics, 2014
The current genetic makeup of Latin America has been shaped by a history of extensive admixture b... more The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú ). These individuals were also characterized for a range of physical appearance traits and for selfperception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.
American Journal of Physical Anthropology, 2015
Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer... more Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer environmental and genetic factors affecting facial phenotypes. However, the genetic basis and environmental determinants of both asymmetry types is far from being completely known. The analysis of facial asymmetries in admixed individuals can be of help to characterize the impact of a genome's heterozygosity on the developmental basis of both fluctuating and directional asymmetries. Here we characterize the association between genetic ancestry and individual asymmetry on a sample of Latin-American admixed populations. To do so, three-dimensional (3D) facial shape attributes were explored on a sample of 4,104 volunteers aged between 18 and 85 years. Individual ancestry and heterozygosity was estimated using more than 730,000 genome-wide markers. Multivariate techniques applied to geometric morphometric data were used to evaluate the magnitude and significance of directional and fluctuating asymmetry (FA), as well as correlations and multiple regressions aimed to estimate the relationship between facial FA scores and heterozygosity and a set of covariates. Results indicate that directional and FA are both significant, the former being the strongest expression of asymmetry in this sample. In addition, our analyses suggest that there are some specific patterns of facial asymmetries characterizing the different ancestry groups. Finally, we find that more heterozygous individuals exhibit lower levels of asymmetry. Our results highlight the importance of including ancestry-admixture estimators, especially when the analyses are aimed to compare levels of asymmetries on groups differing on socioeconomic levels, as a proxy to estimate developmental noise. Am J Phys Anthropol, 2015. © 2014 Wiley Periodicals, Inc.
PloS one, 2014
The understanding of the complex genotype-phenotype architecture of human pigmentation has clear ... more The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for the evolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previously been associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing on populations outside the European-North American axis are rare, and, until now, admixed populations have seldom been considered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18 single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) in two admixed Brazilian populations (Gaucho, N = 352; Baiano, N = 148) with different histories of geographic and ethnic colonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two (SLC24A5 rs1426654, and SLC45A2 rs16891982...
PLoS genetics, 2007
We examined genetic diversity and population structure in the American landmass using 678 autosom... more We examined genetic diversity and population structure in the American landmass using 678 autosomal microsatellite markers genotyped in 422 individuals representing 24 Native American populations sampled from North, Central, and South America. These data were analyzed jointly with similar data available in 54 other indigenous populations worldwide, including an additional five Native American groups. The Native American populations have lower genetic diversity and greater differentiation than populations from other continental regions. We observe gradients both of decreasing genetic diversity as a function of geographic distance from the Bering Strait and of decreasing genetic similarity to Siberians--signals of the southward dispersal of human populations from the northwestern tip of the Americas. We also observe evidence of: (1) a higher level of diversity and lower level of population structure in western South America compared to eastern South America, (2) a relative lack of dif...
The large and diverse population of Latin America is potentially a powerful resource for elucidat... more The large and diverse population of Latin America is potentially a powerful resource for elucidating the genetic basis of complex traits through admixture mapping. However, no genome-wide characterization of admixture across Latin America has yet been attempted. Here, we report an analysis of admixture in thirteen Mestizo populations (i.e. in regions of mainly European and Native settlement) from seven countries in Latin America based on data for 678 autosomal and 29 Xchromosome microsatellites. We found extensive variation in Native American and European ancestry (and generally low levels of African ancestry) among populations and individuals, and evidence that admixture across Latin America has often involved predominantly European men and both Native and African women. An admixture analysis allowing for Native American population subdivision revealed a differentiation of the Native American ancestry amongst Mestizos. This observation is consistent with the genetic structure of pre-Columbian populations and with admixture having involved Natives from the area where the Mestizo examined are located. Our findings agree with available information on the demographic history of Latin America and have a number of implications for the design of association studies in population from the region.
American Journal of Botany, 1988
by Aloyz R, Juan Dib, Claudia Moreau, S. Fedorova, Alejandra Contreras, Samuel Canizales-quinteros, Giovanni Poletti, Gabriel Berrío, Carla Gallo, Rem Sukernik, Maria-Luiza Petzl-Erler, Arti Tandon, Nick Patterson, and Irma Silva-Zolezzi Nature, 2012
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Papers by Giovanni Poletti