Hasil untuk "History America"

S. Schiffels, R. Durbin

The availability of complete human genome sequences from populations across the world has given rise to new population genetic inference methods that explicitly model ancestral relationships under recombination and mutation. So far, application of these methods to evolutionary history more recent than 20,000–30,000 years ago and to population separations has been limited. Here we present a new method that overcomes these shortcomings. The multiple sequentially Markovian coalescent (MSMC) analyzes the observed pattern of mutations in multiple individuals, focusing on the first coalescence between any two individuals. Results from applying MSMC to genome sequences from nine populations across the world suggest that the genetic separation of non-African ancestors from African Yoruban ancestors started long before 50,000 years ago and give information about human population history as recent as 2,000 years ago, including the bottleneck in the peopling of the Americas and separations within Africa, East Asia and Europe.

N. Patterson, Priya Moorjani, Yontao Luo et al.

Population mixture is an important process in biology. We present a suite of methods for learning about population mixtures, implemented in a software package called ADMIXTOOLS, that support formal tests for whether mixture occurred and make it possible to infer proportions and dates of mixture. We also describe the development of a new single nucleotide polymorphism (SNP) array consisting of 629,433 sites with clearly documented ascertainment that was specifically designed for population genetic analyses and that we genotyped in 934 individuals from 53 diverse populations. To illustrate the methods, we give a number of examples that provide new insights about the history of human admixture. The most striking finding is a clear signal of admixture into northern Europe, with one ancestral population related to present-day Basques and Sardinians and the other related to present-day populations of northeast Asia and the Americas. This likely reflects a history of admixture between Neolithic migrants and the indigenous Mesolithic population of Europe, consistent with recent analyses of ancient bones from Sweden and the sequencing of the genome of the Tyrolean “Iceman.”

S. Tishkoff, F. A. Reed, F. Friedlaender et al.

African Origins The modern human originated in Africa and subsequently spread across the globe. However, the genetic relationships among the diverse populations on the African continent have been unclear. Tishkoff et al. (p. 1035; see the cover, published online 30 April) provide a detailed genetic analysis of most major groups of African populations. The findings suggest that Africans represent 14 ancestral populations. Populations tend to be of mixed ancestry which documents historical migrations. The data mainly support but sometimes challenge proposed relationships between groups of self-identified ethnicity previously hypothesized on the basis of linguistic studies. The authors also examined populations of African Americans and individuals of mixed ancestry from Cape Town, documenting the variation and origins of admixture within these groups. A genetic study illuminates population history, as well as the relationships among and the origin of major language families. Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies.

J. Skyler, G. Bakris, E. Bonifacio et al.

The American Diabetes Association, JDRF, the European Association for the Study of Diabetes, and the American Association of Clinical Endocrinologists convened a research symposium, “The Differentiation of Diabetes by Pathophysiology, Natural History and Prognosis” on 10–12 October 2015. International experts in genetics, immunology, metabolism, endocrinology, and systems biology discussed genetic and environmental determinants of type 1 and type 2 diabetes risk and progression, as well as complications. The participants debated how to determine appropriate therapeutic approaches based on disease pathophysiology and stage and defined remaining research gaps hindering a personalized medical approach for diabetes to drive the field to address these gaps. The authors recommend a structure for data stratification to define the phenotypes and genotypes of subtypes of diabetes that will facilitate individualized treatment.

D. D. Murphey

R. Cann

J. Hage, R. Hollingsworth, F. Fukuyama

K. Poole, H. Rosenthal

S. Weaver, F. Costa, M. Garcia-Blanco et al.

M. Raghavan, Matthias Steinrücken, Kelley Harris et al.

M. Seligman

As president of the American Psychological Association in 1998, I organized researchers and practitioners to work on building well-being, not just on the traditional task of reducing ill-being. Substantial research then found that well-being causes many external benefits, including better physical and mental health. Among the applications of Positive Psychology are national psychological accounts of well-being, Positive Psychotherapy, the classification of strengths and virtues, Comprehensive Soldier Fitness, and Positive Education. Positive Psychology has spread beyond psychology into neuroscience, health, psychiatry, theology, and even to the humanities. Positive Psychology has many critics, and I comment on the strongest criticisms. I conclude with the hope that the building of well-being will become a cornerstone of morality, politics, and religion.

D. Howe

M. Sikora, V. Pitulko, V. Sousa et al.

Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of ‘Ancient North Siberians’ who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to ‘Ancient Palaeo-Siberians’ who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name ‘Neo-Siberians’, and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas. Analyses of 34 ancient genomes from northeastern Siberia, dating to between 31,000 and 600 years ago, reveal at least three major migration events in the late Pleistocene population history of the region.

P. Wolfe

Eldi Paola Robayo

The export of security-related know-how has become a strategic component of Colombia’s foreign policy over the past two decades. This article aims to describe and analyze the role of the National Police of Colombia in this export between 2010 and 2022. Using a mixed methodological approach that combines qualitative analysis and the systematization of quantitative data, it examines the institutional guidelines underpinning this policy, the volume and characteristics of the training programs offered, and the deployment of experts abroad. Additionally, the cases of Mexico and Honduras are analyzed in depth as representative cooperation experiences. The article highlights the functioning of the triangular cooperation model, in which Colombia provides training while the United States contributes funding and logistical support. The analysis identifies the implications of this strategy, including its alignment with a militarized security approach, the limited evaluation of its actual impacts, and the risks of replicating problematic practices in institutionally fragile contexts.

Ran Abramitzky, L. Boustan

Cecilia Mafla

Archivo histórico de Kipus: Revista Andina de Letras y Estudios Culturales, 2005.

Julio Pinto Vallejos

Como homenaje a Jorge Gelman, este artículo resume los resultados de una investigación comparativa sobre la temprana formación de estado en tres países sudamericanos: Argentina, Perú y Chile. Tomando como eje analítico los esfuerzos de recomposición de hegemonía desplegados por tres liderazgos caudillistas (Juan Manuel de Rosas, Ramón Castilla y Diego Portales), se exploran los procesos de negociación, incorporación y exclusión de sectores populares que el artículo denomina “construcción social del estado”. Se concluye que, a partir de una tarea común de restablecimiento del orden, los tres casos estudiados aplicaron estrategias y dosis diferentes de imposición o seducción, derivando en resultados igualmente disímiles en materia de adhesiones plebeyas e inclusión social.

J. Brubacher

Christine Focquenoy Simonnet