A. C. B. Sousa

Isolation and characterization of microsatellite loci in Pitcairnia albiflos (Bromeliaceae), an endemic bromeliad from the Atlantic Rainforest, and cross-amplification in other species

Eight microsatellite markers were isolated from Pitcairnia albiflos, an endangered endemic bromeliad species restricted to ‘inselberg’ rock outcrops in the state of Rio de Janeiro, Brazil. The number of alleles observed for each locus ranged from two to 12. Average observed and expected heterozygosities were 0.408 and 0.663, respectively. The cross‐amplification test in 16 taxa suggests that the markers will be useful in numerous related bromeliad species. The loci will be used to study genetic structure and reproductive biology in fragmented inselberg populations and the origin and maintenance of barriers to gene flow between sympatric Pitcairnia species.

Development of microsatellite markers for Brachiaria humidicola (Rendle) Schweick

We describe the first panel of nuclear simple sequence repeats (SSRs) loci for Brachiaria humidicola (Rendle) Schweick., a warmseason grass with facultative apomixis, variation in ploidy levels (6X–9X), and important forage grass species in the Tropics. Of 38 pairs of primers obtained by using an enriched-library methodology, 27 revealed polymorphism in 58 accessions of the Germplasm Collection of B. humidicola held at Embrapa Beef Cattle, Brazil. Eleven loci amplified in B. dictyoneura, a closely related species with unclear taxonomic boundaries with B. humidicola. Transferability to other three Brachiaria species was also evaluated. The developed microsatellites are potentially useful for genetic studies of B. humidicola, as well as phylogenetic evaluations, conservation and breeding applications.

DNA microsatellite markers for “dourada” (Brachyplatystoma rousseauxii, Siluriformes: Pimelodidae), a migratory catfish of utmost importance for fisheries in the Amazon: development, characterization and inter-specific amplification

The long-distance migratory catfish Brachyplatystoma rousseauxii is among the two most important commercial catfish in the Amazon region. Recent data lists this species as being affected by overfishing. Thirty polymorphic microsatellite loci were isolated and characterized in 35 individuals. The number of alleles per locus ranged from 2 to 22, with an average of 9.87. The observed (HO) and the expected heterozygosity (HE) ranged between 0.143–0.914 (average 0.636) and 0.215–0.929 (average 0.706), respectively. Five loci showed a significant deviation from the Hardy–Weinberg Equilibrium and linkage disequilibrium was detected between loci BR68/BR44, BR68/BR48 and BR68/BR61. Cross-amplification in six con-generic species resulted between 12 and 21 polymorphic loci, depending upon the species. These polymorphic microsatellites should be useful for management policies of B. rousseauxii in the Amazon as well as for the others Brachyplatystoma species of commercial value.

Isolation and characterization of microsatellite markers for Brachiaria brizantha (Hochst. ex A. Rich.) Stap

The first set of nuclear simple sequence repeat (SSR) loci for Brachiaria brizantha (Hochst. ex A. Rich.) Stap is described. A microsatellite-enriched library was constructed and 19 loci were characterized. About 13 SSR loci were found to be polymorphic and across-taxa amplification tests showed that six of them can be transferred to four other species of Brachiaria. This new SSR resource will be a powerful tool for population genetic studies of B. brizantha, for interspecific genetic studies within the genus Brachiaria, for mapping and for marker assisted selection in breeding.

Isolation and characterization of microsatellite loci in the stingless bee Melipona interrupta manaosensis (Apidae: Meliponini)

Melipona interrupta manaosensis is an important pollinator in the Neotropics. This stingless bee is reared by locals for honey production and also for conservation purposes. Eleven microsatellite markers were isolated from M. i. manaosensis and characterized in 32 individuals from the Meliponary of the Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil. The number of alleles observed for each locus ranged from 2 to 5 (average 2.77). The polymorphism information content (PIC) varied between 0.08 to 0.62 (average 0.34) and the discriminating power (D) ranged from 0.61 to 0.99 (average 0.85). The observed heterozygosity (HO) and the expected heterozygosity (HE) ranged from 0.04 to 1.00 and 0.04 to 0.67, respectively. These microsatellites will be useful for future genetic studies of M. i. manaosensis populations and correlated species contributing with Amazon biodiversity preservation.

Temporal genetic structure of major dengue vector Aedes aegypti from Manaus, Amazonas, Brazil

In recent years, high levels of Aedes aegypti infestation and several dengue outbreaks with fatal outcome cases have been reported in Manaus, State of Amazonas, Brazil. This situation made it important to understand the genetic structure and gene flow patterns among the populations of this vector in Manaus, vital pieces of information for their management and development of new control strategies. In this study, we used nine microsatellite loci to examine the effect of seasonality on the genetic structure and gene flow patterns in Ae. aegypti populations from four urban neighborhoods of Manaus, collected during the two main rainy and dry seasons. All loci were polymorphic in the eight samples from the two seasons, with a total of 41 alleles. The genetic structure analyses of the samples from the rainy season revealed genetic homogeneity and extensive gene flow, a result consistent with the abundance of breeding sites for this vector. However, the samples from the dry season were significantly structured, due to a reduction of Ne in two (Praça 14 de Janeiro and Cidade Nova) of the four samples analyzed, and this was the primary factor influencing structure during the dry season. Genetic bottleneck analyses suggested that the Ae. aegypti populations from Manaus are being maintained continuously throughout the year, with seasonal reduction rather than severe bottleneck or extinction, corroborating previous reports. These findings are of extremely great importance for designing new dengue control strategies in Manaus.

Isolation of novel microsatellite markers for tambaqui ( Colossoma macropomum , Cuvier 1818), an important freshwater fish of the Amazon

Colossoma macropomum is an endemic species from Amazon basin. It is widely commercialized as food, becoming one of the main items in Amazonian fisheries. Despite its economic importance, genetic information of small captivity populations is not currently available. The present contribution describes 14 new microsatellite loci used to analyze 30 individuals of C. macropomum. The number of alleles for each locus ranged from 4 to 24. The observed (Ho) and expected (HE) heterozygosity values ranged from 0.318 to 1.000 and 0.729 to 0.949, respectively. Out of 14 polymorphic loci, nine did not deviate from Hardy–Weinberg Equilibrium after Bonferroni correction. These new microsatellite loci will contribute towards the genetic of small artificial populations, as well as pedigree control of fish farms of C. macropomum.

Molecular Diversity and Genetic Structure of Guineagrass (Panicum maximum Jacq.), a Tropical Pasture Grass

Guineagrass (Panicum maximum Jacq.) is a forage grass found in tropical and subtropical regions. It is an apomictic and tetraploid species from Africa. The objective of this study was to evaluate the genetic diversity of guineagrass accessions sampled from its regions of origin, which is in Tanzania and Kenya. In this study, a total of 396 accessions were analyzed, and a collection of reproducible and informative microsatellites was developed. Thirty microsatellites were employed to characterize these accessions. A total of 576 clones were sequenced from microsatellite-enriched libraries. Flanking primers were designed for 116 microsatellite loci and screened using a sample of 25 guineagrass accessions. The thirty selected polymorphic microsatellites employed in this study produced a total of 192 bands when evaluated in the 396 P. maximum accessions, with an average of 6.4 bands per microsatellite. Four genetic clusters were identified in the collection using STRUCTURE analysis, and these results were confirmed using AMOVA. The largest genetic variation was found within clusters (65.38%). This study revealed that the collection of accessions from the P. maximum region of origin was a rich source of genetic variability. The geographical distances and genetic similarities among accessions did not indicate a significant association between genetic and geographical variation, supporting the natural interspecific crossing between P. maximum, P. infestum and P. trichocladum as the origin of the high genetic variability and the existence of an agamic complex formed by these three species.

Isolation and characterization of microsatellite markers from the stingless bee Nannotrigona testaceicornis

Conservation of natural populations and handling of breeding programs would benefit from the availability of molecular markers. Stingless bees are one of the most important pollinators in several ecosystems. Thus, seventeen microsatellite markers were developed from an enriched genomic library of Nannotrigona testaceicornis. They were characterized using 50 samples. The expected and observed heterozygosities ranged from 0.59 to 0.89 and from 0.39 to 0.79, respectively. These markers will contribute to advance researches on the genetic conservation, characterization and preservation of the Brazilian native bees.

Potato cultivar identification using molecular markers

O objetivo deste trabalho foi avaliar um conjunto de marcadores microssatelites para identificacao e caracterizacao varietal das cultivares de batata mais amplamente utilizadas no Brasil. O DNA das 14 variedades de batata foi genotipado com marcadores microssatelites, e os alelos foram visualizados em gel de poliacrilamida corado com prata. Vinte e quatro marcadores foram avaliados e apenas um loco foi monomorfico. Com base no padrao de bandas, foi obtido um conjunto com dois microssatelites capazes de identificar e diferenciar todas as cultivares analisadas.