Análise físico-química do óleo-resina e variabilidade genética de copaíba na Floresta Nacional do Tapajós

O objetivo deste trabalho foi caracterizar o óleo-resina da copaíba (Copaifera reticulata) e estimar, por meio de marcadores microssatélites, a variabilidade genética da espécie na Floresta Nacional do Tapajós, PA. A amostragem foi realizada em duas áreas, distanciadas de 5 km, em 136 árvores. A diversidade genética foi avaliada com seis marcadores microssatélites derivados de C. langsdorffii, e o óleo obtido de 30 árvores (15 de cada área) foi caracterizado em termos físicos e químicos. O óleo C. reticulata apresenta aspecto líquido, fino, odor fraco e de coloração amarelo-dourada (73,3% das plantas), com viscosidade muito variável (18 a 187 Pa-s) e densidade média de 0,975±0,049 g cm-3. O índice de acidez variou de 9,62 a 10,17 mg g-1 de KOH e o de saponificação de 100,63 a 109,84 mg g-1. A análise molecular identificou 78 alelos, com média de 13 por loco. A heterozigosidade esperada variou 0,59 a 0,85 (média de 0,75), com nível de endogamia de 0,375 a 0,419. Houve pouca diferenciação genética entre as populações das diferentes áreas de coleta (F ST = 0,030), mas a variabilidade foi maior entre os grupos genéticos detectados pelo programa Structure (F ST = 0,070). Essa maior variabilidade indica que não há ameaças à conservação genética da copaíba, em médio prazo

Population structure and genetic diversity of New World maize races assessed by DNA microsatellites

Because of the economic importance of maize and its scientific importance as a model system for studies of domestication, its evolutionary history is of general interest. We analyzed the population genetic structure of maize races by genotyping 964 individual plants, representing almost the entire set of ?350 races native to the Americas, with 96 microsatellites. Using Bayesian clustering, we detected four main clusters consisting of highland Mexican, northern United States (US), tropical lowland, and Andean races. Phylogenetic analysis indicated that the southwestern US was an intermediary stepping stone between Mexico and the northern US. Furthermore, southeastern US races appear to be of mixed northern flint and tropical lowland ancestry, while lowland middle South American races are of mixed Andean and tropical lowland ancestry. Several cases of post-Columbian movement of races were detected, most notably from the US to South America. Of the four main clusters, the highest genetic diversity occurs in highland Mexican races, while diversity is lowest in the Andes and northern US. Isolation by distance appears to be the main factor underlying the historical diversification of maize. We identify highland Mexico and the Andes as potential sources of genetic diversity underrepresented among elite lines used in maize breeding programs

Fifteen-year trends of long-term disability and sick leaves in ankylosing spondylitis

Analysis of fine scale genetic structure in continuous populations of outcrossing plant species has traditionally been limited by the availability of sufficient markers. We used a set of 468 SNPs to characterize fine-scale genetic structure within and between two dense stands of the wild ancestor of maize, teosinte (Zea mays ssp. parviglumis). Our analyses confirmed that teosinte is highly outcrossing and showed little population structure over short distances. We found that the two populations were clearly genetically differentiated, although the actual level of differentiation was low. Spatial autocorrelation of relatedness was observed within both sites but was somewhat stronger in one of the populations. Using principal component analysis, we found evidence for significant local differentiation in the population with stronger spatial autocorrelation. This differentiation was associated with pronounced shifts in the first two principal components along the field. These shifts corresponded to changes in allele frequencies, potentially due to local topographical features. There was little evidence for selection at individual loci as a contributing factor to differentiation. Our results demonstrate that significant local differentiation may, but need not, co-occur with spatial autocorrelation of relatedness. The present study represents one of the most detailed analyses of local genetic structure to date and provides a benchmark for future studies dealing with fine scale patterns of genetic diversity in natural plant populations. " 2010 Blackwell Publishing Ltd.",,,,,,"10.1111/j.1365-294X.2010.04559.x",,,"http://hdl.handle.net/20.500.12104/41510","http://www.scopus.com/inward/record.url?eid=2-s2.0-77950292826&partnerID=40&md5=095b598a34a7094c855c5ccf81686a4f",,,,,,"6",,"Molecular Ecology",,"116

Megabase-scale inversion polymorphism in the wild ancestor of maize

Chromosomal inversions are thought to play a special role in local adaptation, through dramatic suppression of recombination, which favors the maintenance of locally adapted alleles. However, relatively few inversions have been characterized in population genomic data. On the basis of single-nucleotide polymorphism (SNP) genotyping across a large panel of Zea mays, we have identified an ~50-Mb region on the short arm of chromosome 1 where patterns of polymorphism are highly consistent with a polymorphic paracentric inversion that captures > 700 genes. Comparison to other taxa in Zea and Tripsacum suggests that the derived, inverted state is present only in the wild Z. mays subspecies parviglumis and mexicana and is completely absent in domesticated maize. Patterns of polymorphism suggest that the inversion is ancient and geographically widespread in parviglumis. Cytological screens find little evidence for inversion loops, suggesting that inversion heterozygotes may suffer few crossover-induced fitness consequences. The inversion polymorphism shows evidence of adaptive evolution, including a strong altitudinal cline, a statistical association with environmental variables and phenotypic traits, and a skewed haplotype frequency spectrum for inverted alleles. © 2012 by the Genetics Society of America

The relationship between china and Siberia/Russian Far East: Economic cooperation and security conflicts

This paper analyzes the current relationship between China and Siberia/Russian Far East from the economic and political-security perspectives. The relationship between China and Siberia/Russian Far East is that of cooperation and conflict. China gains natural resources and energy from Siberia/Russian Far East, while Siberia/Russian Far East secures consumer goods, food and labor to fill its shortage from China. The two regions are in an economically complementary relationship. However, they show differences in their interests in issues such as the Tuman River Development Project. If their economic cooperation could be called the “bright” side of their relationship, there exists the “dark” side of their relationship, which is the border dispute. The paper argues that as a way to reduce conflict and increase cooperation in Northeast Asia, a multilateral security/economic organization, tentatively called the “Organization for Security and Cooperation in Northeast Asia,” should soon be established.