Abstract In spite of many genetic studies that contributed for a deep knowledge about the peopling of the Americas, no consensus has emerged about important parameters such as the effective size of the Native Americans founder population. Previous estimates based on genomic datasets may have been biased by the use of admixed individuals from Latino populations, while other recent studies using samples from Native American individuals relied on approximated analytical approaches. In this study we use resequencing data for nine independent regions in a set of Native American and Siberian individuals and a full-likelihood approach based on isolation-with-migration scenarios accounting for recent flow between Asian and Native American populations. Our results suggest that, in agreement with previous studies, the effective size of the Native American population was small, most likely in the order of a few hundred individuals, with point estimates close to 250 individuals, even though credible intervals include a number as large as ~4,000 individuals. Recognizing the size of the genetic bottleneck during the peopling of the Americas is important for determining the extent of genetic markers needed to characterize Native American populations in genome-wide studies and to evaluate the adaptive potential of genetic variants in this population.

Abstract After a brief introduction about the factors that are involved in science development, and world and Brazilian evolutionary genetics, the studies developed in Porto Alegre in this area were reviewed. Four periods in the development of this group were distinguished: (a) Origins and first expansion (1949-1961); (b) Second expansion (1962-1988); (c) Third expansion (1989-2001); and (d) The last 15 years (2002-present). The international Porto Alegre Biological Evolution Workshops (PABEWs), with five biannual events from 2007 o 2015, were also mentioned. The final message stressed the importance of the maintenance of this and other Brazilian groups of research through adequate finance and recognition.

Abstract Alcohol dehydrogenases belong to the large superfamily of medium-chain dehydrogenases/reductases, which occur throughout the biological world and are involved with many important metabolic routes. We considered the phylogeny of 190 ADH sequences of animals, fungi, and plants. Non-class III Caenorhabditis elegans ADHs were seen closely related to tetrameric fungal ADHs. ADH3 forms a sister group to amphibian, reptilian, avian and mammalian non-class III ADHs. In fishes, two main forms are identified: ADH1 and ADH3, whereas in amphibians there is a new ADH form (ADH8). ADH2 is found in Mammalia and Aves, and they formed a monophyletic group. Additionally, mammalian ADH4 seems to result from an ADH1 duplication, while in Fungi, ADH formed clusters based on types and genera. The plant ADH isoforms constitute a basal clade in relation to ADHs from animals. We identified amino acid residues responsible for functional divergence between ADH types in fungi, mammals, and fishes. In mammals, these differences occur mainly between ADH1/ADH4 and ADH3/ADH5, whereas functional divergence occurred in fungi between ADH1/ADH5, ADH5/ADH4, and ADH5/ADH3. In fishes, the forms also seem to be functionally divergent. The ADH family expansion exemplifies a neofunctionalization process where reiterative duplication events are related to new activities.

Abstract A brief introduction considering Darwin's work, the evolutionary synthesis, and the scientific biological field around the 1970s and subsequently, with the molecular revolution, was followed by selected examples of recent investigations dealing with the selection-drift controversy. The studies surveyed included the comparison between essential genes in humans and mice, selection in Africa and Europe, and the possible reasons why females in humans remain healthy and productive after menopause, in contrast with what happens in the great apes. At the end, selected examples of investigations performed in Latin America, related to the action of selection for muscle performance, acetylation of xenobiotics, high altitude and tropical forest adaptations were considered. Despite dissenting views, the influence of positive selection in a considerable portion of the human genome cannot presently be dismissed.

The population of Argentina has already been studied with regard to several genetic markers, but much more data are needed for the appropriate definition of its genetic profile. This study aimed at investigating the admixture patterns and genetic structure in Central Argentina, using biparental markers and comparing the results with those previously obtained by us with mitochondrial DNA (mtDNA) in the same samples. A total of 521 healthy unrelated individuals living in 13 villages of the Córdoba and San Luis provinces were tested. The individuals were genotyped for ten autosomal ancestry informative markers (AIMs). Allele frequencies were compared with those of African, European and Native American populations, chosen to represent parental contributions. The AIM estimates indicated a greater influence of the Native American ancestry as compared to previous studies in the same or other Argentinean regions, but smaller than that observed with the mtDNA tests. These differences can be explained, respectively, by different genetic contributions between rural and urban areas, and asymmetric gene flow occurred in the past. But a most unexpected finding was the marked interpopulation genetic homogeneity found in villages located in diverse geographic environments across a wide territory, suggesting considerable gene flow.

The world view in the Dark (Middle Ages) could not be more monotonous. The world would have been created by a divine entity in a fixed version, and divergent opinions would be considered a heresy and subjected to strong opposition by the church. Everything changed with the publication in 1859 of Charles Darwin's seminal work The Origin of Species. Nature was not created to serve us; instead, the human species was just one in a multitude of other biological entities. To this Darwinian revolution others followed in the ensuing one and a half century, involving: a) The Modern synthesis, b) elucidation of the structure of the genetic material, c) techniques of DNA manipulation, and d) bioinformatics and nanotechnology. The half-a-century investigations of our group followed these changes, and examples of some of the most recent will be described, involving: 1. comparisons between archaic and modern genomes, 2. genomic approaches to Amerindian history, and 3. gene-culture interactions involving specific traits. Molecular and bioinformatic techniques are allowing us to have a detailed view of our past, better understanding of our present, and conditions to better predict our future.

La visión del mundo en el oscurantismo (Edad Media) no podría ser más monótona. La versión establecida era que el mundo había sido creado por una entidad divina y las opiniones divergentes se consideraban una herejía y enfrentaban la fuerte oposición de la Iglesia. Todo cambió con la publicación, en 1859, de la obra precursora de Charles Darwin, El origen de las especies. La naturaleza no fue creada para servirnos; la especie humana, más bien, fue sólo una más en una multitud de otras entidades biológicas. A esta revolución darwiniana le siguieron otras en el siglo subsiguiente y el siguiente medio siglo, las cuales implicaron: a) la síntesis evolutiva moderna, b) la dilucidación de la estructura del material genético; c) las técnicas de manipulación del ADN y d) la bioinformática y la nanotecnología. El medio siglo de investigaciones de nuestro grupo continuó con estos cambios, entre los más recientes se incluyen algunos de los ejemplos que se describen a continuación: 1. comparaciones entre los genomas arcaicos y modernos, 2. enfoques genómicos para la historia amerindia y 3. interacciones entre los genes y la cultura con rasgos específicos. La técnica molecular y la bioinformática nos permiten tener una vista detallada de nuestro pasado así como una mejor comprensión de nuestro presente y de las condiciones que predicen mejor nuestro futuro.

The questions of the title have been considered in several ways. First, indications of the traits which make us humans were considered. Then the behavior and culture concepts were examined, and the biology and culture interactions discussed, with an emphasis on the similarities and differences between the genetic and cultural transmissions. Next diverse types of selective pressures were reviewed, and finally pessimistic and optimistic views of our future contrasted. Vigorous action against acts which lead to exclusion and discriminatory policies against human subjects is needed.

The discovery and characterization of informative intraspecific genetic markers is fundamental for evolutionary and conservation genetics studies. Here, we used nuclear ribosomal ITS sequences to access intraspecific genetic diversity in 23 species of the genus Passiflora L. Some degree of variation was detected in 21 of these. The Passiflora and Decaloba (DC.) Rchb. subgenera showed significant differences in the sizes of the two ITS regions and in GC content, which can be related to reproductive characteristics of species in these subgenera. Furthermore, clear geographical patterns in the spatial distribution of sequence types were identified in six species. The results indicate that ITS may be a useful tool for the evaluation of intraspecific genetic variation in Passiflora.

Two hundred and three individuals classified as white were tested for 11 single nucleotide polymorphisms plus two insertion/deletions in their Y-chromosomes. A subset of these individuals (n = 172) was also screened for sequences in the first hypervariable segment of their mitochondrial DNA (mtDNA). In addition, complementary studies were done for 11 of the 13 markers indicated above in 54 of 107 black subjects previously investigated in this southern Brazilian population. The prevalence of Y-chromosome haplogroups among whites was similar to that found in the Azores (Portugal) or Spain, but not to that of other European countries. About half of the European or African mtDNA haplogroups of these individuals were related to their places of origin, but not their Amerindian counterparts. Persons classified in these two categories of skin color and related morphological traits showed distinct genomic ancestries through the country. These findings emphasize the need to consider in Brazil, despite some general trends, a notable heterogeneity in the pattern of admixture dynamics within and between populations/groups.

O vírus linfotrópico de células T-humanas do tipo II (HTLV-II) é identificado em muitos grupos de ameríndios. No Brasil, tem sido encontrado em indivíduos da população urbana, bem como em índios oriundos da região Amazônica. Os Índios Guaraní, do Sul do país, foram investigados para infecção por HTLV-I/II. Três indivíduos, oriundos de uma amostra de 52 índios, demonstraram sororeatividade para HTLV-II (ensaio imunoenzimático e Western blot). Este estudo preliminar foi o primeiro a identificar a presença de infecção por HTLV-II em ameríndios do Sul do Brasil.

Human T-cell lymphotropic virus type II (HTLV-II) is found in many New World Indian groups on the American continent. In Brazil, HTLV-II has been found among urban residents and Indians in the Amazon region, in the North. Guaraní Indians in the South of Brazil were studied for HTLV-I/II infection. Among 52 individuals, three (5.76%) showed positive anti-HTLV-II antibodies (enzyme-linked immunosorbent assay and Western blot). This preliminary report is the first seroepidemiological study showing HTLV-II infection among Indians in the South of Brazil.

O vírus linfotrópico de células T-humanas do tipo II (HTLV-II) é identificado em muitos grupos de ameríndios. No Brasil, tem sido encontrado em indivíduos da população urbana, bem como em índios oriundos da região Amazônica. Os Índios Guaraní, do Sul do país, foram investigados para infecção por HTLV-I/II. Três indivíduos, oriundos de uma amostra de 52 índios, demonstraram sororeatividade para HTLV-II (ensaio imunoenzimático e Western blot). Este estudo preliminar foi o primeiro a identificar a presença de infecção por HTLV-II em ameríndios do Sul do Brasil.

Human T-cell lymphotropic virus type II (HTLV-II) is found in many New World Indian groups on the American continent. In Brazil, HTLV-II has been found among urban residents and Indians in the Amazon region, in the North. Guaraní Indians in the South of Brazil were studied for HTLV-I/II infection. Among 52 individuals, three (5.76%) showed positive anti-HTLV-II antibodies (enzyme-linked immunosorbent assay and Western blot). This preliminary report is the first seroepidemiological study showing HTLV-II infection among Indians in the South of Brazil.

The genes encoding 13 classes of pathogenesis-related (PR) proteins were examined for positive selection using maximum-likelihood (ML) models of codon substitution. The study involved 194 sequences from 54 species belonging to 37 genera. Although the sizes of the sequences examined varied from 237 bp for PR12 to 1,110 bp for PR7, most classes (9 out of 13) contained sequences made up of more than 400 nucleotides. Signs of positive selection were obtained for sites in PR proteins 4, 6, 8, 9 and 15 using an ML-based Bayesian method and likelihood ratio tests. These results confirm the importance of positive selection in proteins related to defense mechanisms already observed in a wide array of organisms.

A presente revisão considerou: (a) os fatores que condicionaram a transição inicial entre não-vida e vida; (b) a estrutura e complexidade genômica em procariotos, eucariotos e organelas; (c) a genômica comparada dos cromossomos humanos; (d) a contribuição brasileira a alguns desses estudos. A compreensão do conflito dialético entre liberdade e organização é fundamental para dar significado aos padrões e processos da evolução orgânica.

The present review considered: (a) the factors that conditioned the early transition from non-life to life; (b) genome structure and complexity in prokaryotes, eukaryotes, and organelles; (c) comparative human chromosome genomics; and (d) the Brazilian contribution to some of these studies. Understanding the dialectical conflict between freedom and organization is fundamental to give meaning to the patterns and processes of organic evolution.