Maria Rosa Costa

Similaridade genética de cultivares de mandioca (Manihot esculenta) por meio de marcadores RAPD

O objetivo deste trabalho foi analisar a divergencia genetica entre 27 acessos de mandioca provenientes do banco ativo de germoplasma da Embrapa Amazonia Oriental. Foram utilizados 12 primers, onde todos apresentaram polimorfismo. Foram analisadas 73 bandas polimorficas de um total de 211 bandas amplificadas. A analise de divergencia genetica foi realizada a partir do programa NTSYS-pc, 2.02, utilizando o coeficiente de Jaccard. Na analise do dendograma, foram observados dois grupos principais. No primeiro grupo, que se subdividiu em dois subgrupos, com coeficiente de similaridade, variando de 8% a 78%, incluem-se 20 materiais, oriundos de diferentes localidades. O segundo grupo dividiu-se em dois subgrupos, com similaridade genetica, variando de 9% a 38%. Os acessos CPATU 260 e CPATU 137 foram distintos, em relacao ao restante, constituindo subgrupos isolados, dentro do seu grupo. Os resultados obtidos mostraram variabilidade genetica potencial para o programa de melhoramento genetico e informacoes uteis, para o direcionamento de coleta de germoplasma de mandioca para enriquecimento do BAG.

Similaridade genética de populações naturais de pimenta-de-macaco por análise RAPD

The species known as pimenta-de-macaco (Piper aduncum L.) has great economic explotation potential based on the proved usefulness of the essential oil in agriculture and human health. The genetic diversity of their natural populations was characterized. A total of eighteen accessions of the plant, obtained from four different origins in the Brazilian Amazon, was examined by means of DNA loci, generated by RAPD analysis. Real genetic diversity was observed between the analyzed populations and it appear that the patterns of the genetic diversity follow the patterns of the geographical distribution.

Caracterização de acessos de pimenta-do-reino com base em sistemas enzimáticos

Seventy and eight accessions of black pepper, including some wild species, were analyzed through isozyme electrophoresis in polyacrylamide gel, aiming to distinguish phenotypic differences to discriminate and select accessions. The enzymatic systems SKDH, GOT, ACO, ACP, PGI, FUM, 6PGDH and G6PDH were studied. The polymorphism of isozymes was evaluated based on number of alozymes with different mobility for each enzymatic system, the frequencies of alozymes within each enzymatic system in relation to the total of bands of the system and, the analysis of the genetic similarity, based on the absence or presence of bands. All the enzymatic systems presented good resolution and definition of bands, with emphasis on SKDH, 6GPDH, PGI and the ACP. All the systems presented sufficient polymorphism to characterize and to identify accessions or groups with little number of accessions, where the GOT system presented better variability of alozymes. On the other hand, FUM system revealed only three alozymes and four profiles. Fifty seven percent of alozymes are efficient to characterize and to identify clones or groups of clones. About sixty four percent of the analyzed accessions can be identified per one to six individual phenotypes of enzymatic systems. The analysis of similarity indicated the G1, G2 and G3 groups as the most divergent, being appropriate for intra or interspecific crossings aiming to obtain superior clones.

Diversidade e similaridade genéticas em clones de pimenta-do-reino

Seventy eight black pepper clones (Piper nigrum L.) were analyzed by means of isozyme electrophoresis for the systems ACP, GOT, SKDH, ACO, G6PDH, PGI, 6PGDH and FUM, in order to evaluate the diversity through the percentage of polymorphic loci, mean number of alleles per locus and mean heterozigosity. Genetic similarity was calculated by simple matching coefficient and summarized in the group average phenogram. Fourteen loci and 35 alleles were detected. The loci that presented larger diversity were G6pdh-1, Acp-1 and Skdh-1. The percentage of polymorphic loci ranged from 3.57% to 64.29%; the mean number of alleles ranged from 0.04 to 1.64 and; the mean heterozigosity varied from 0.036 to 0.321. The lower values observed in the interval of variation of the average heterozigosity are consistent with the narrow genetic basis and the width of this interval can be related to the natural or forced hybridization degree of each clone. The genetic similarity ranged from 65% to 100%, and 70 clones were ranked into the interval of 85% to 100%, which confirms the narrowing of the genetic basis of the species and thereby resulting in the homogeneity of the cultivated clones.

Cytogenetic Characterization of Brazil Origin Marajoara Horses

The Marajoara breed of horses is an important animal group genetically conserved on the island of Marajo, State of Para, Brazil. This breed exhibits very specific characteristics, but has suffered decharacterization as a result of crossing with other naturalized breeds in Brazil. For this reason, Marajoara horses have been introduced into the National Genetic Conservation Program, which includes both ex situ and in situ preservation, and also involves establishing productive, reproductive, genetic and phenotypic parameters for Marajoara horses. Therefore, the aim of this study was the cytogenetic characterization of the Marajoara horses. In order to do it we used the peripheral blood lymphocyte cultures of eight specimens, evaluated in terms of diploid number, morphology, chromosome biometry and C- and NOR-banding patterns. All specimens evaluated had 2n=64 chromosomes and karyotype consisting of submetacentric pairs (1 to 11, 13 and X), a metacentric pair (12) and telocentric pairs (14 to 31 and Y). Cbanding was observed marking centromeric of all complement and interstitial marking feature for X and Y chromosome almost completely heterochromatic. Nucleolus organizer regions were observed in pair 1 in the telomeric region, 28 in interstitial short arm and in 31 near the centromere. The cytogenetic characterization of these animals is the first step in the process of selecting animals for reproduction by establishing the diploid number as a basis for subsequent actions in the genetic conservation program.

Variabilidade genética em muçuã utilizando marcadores moleculares RAPD

O mucua (Kinosternon scorpioides) e uma especie de extrema importância economica no Estado do Para, sendo indispensaveis estudos que viabilizem sua conservacao e sua caracterizacao genetica, a fim de direcionar programas de melhoramento nessa especie e o monitoramento da sua variabilidade. O objetivo foi avaliar a variabilidade genetica existente em populacoes de Kinosternon scorpioides do Banco de Germoplasma Animal da Amazonia Oriental (BAGAM), localizado em Salvaterra, na ilha de Marajo, no Estado do Para, a fim de realizar uma caracterizacao molecular inicial da especie. Foram utilizados marcadores moleculares RAPD (Polimorfismos de DNA Amplificados ao Acaso). Para tanto, foram obtidas amostras de DNA a partir de sangue total de 39 individuos de diferentes populacoes. A selecao de primers foi realizada a partir de um screening de quatro kits (kit OPA, OPU, OPJ, OPM), dos quais foram selecionados os doze mais polimorficos, que geraram bandas no intervalo de tres a oito, viaveis para utilizacao. A analise de similaridade genetica foi realizada com 53 marcadores RAPD, no programa NTSYS-pc, 2.0 utilizando o coeficiente de Jaccard. A partir dos dados gerados pela UPGMA (Unweighted Pair Group Method with Arithmetic Mean), pode-se dimensionar a variabilidade existente entre os mesmos. Foram obtidos intervalos de similaridade genetica variando de 3-98%, sendo que os individuos mais divergentes foram o M8 e o M14 com o M33 (0,03) e os mais similares, os genotipos M3 e o M4 (0,98). Os resultados indicaram a existencia de variabilidade genetica a ser explorada na especie, tanto para programas de melhoramento genetico como para a conservacao da mesma.