Estudos de associaçao de cromossomos acrocentricos humanos em indivíduos portadores de variantes S+

Orientador: Iglenir João CavalliDissertaçao (mestrado) -Universidade Federal do Paraná, Curso de Pós-Graduação em Genética HumanaInclui referências: p. 89-101Resumo: Um dos aspectos que tem sido explorado por ocasião do estudo das variantes cromossômicas menores diz respeito ao comportamento associativo de acrocêntricos portadores de variantes. Uma vez que a função de organizar o nucléolo é papel de certos cromossomos que se associam através da co-orientação de seus satélites, os estudos sobre os padrões de associação, classificados através da identificação do grupo cromossômico, do par cromossômico e até dos homólogos, revelam a participação destes cromossomos na formação do nucléolo. A presença de variantes morfológicas nos acrocêntricos permite a distinção dos homólogos e, consequentemente, a análise comparativa entre- eles. O nosso trabalho teve por objetivo elaborar uma análise semelhante ã comentada acima em uma amostra de dez indivíduos portadores de satélites gigantes. A identificação cromossômica, feita através da técnica de G-bandeamento, permitiu que as associações simples (que perfaziam cerca de 70% da amostra), classificadas em grupos (D-D,1; D-G,2; G-G,3), fossem subdivididas em vários tipos, conforme os cromossomos envolvidos (13-13, 13-14, etc.). Os resultados da análise estatística indicaram que as frequências dos três grupos de associação não se mostraram diferentes e que, por outro lado, os tipos de associação dos grupos 1 e 3 não participaram deles com igual frequência, sendo as associações entre cromossomos homólogos mais raras que as entre heterólogos. A participação dos diversos pares de acrocêntricos , quando consideradas as associações simples e múltiplas, foi casual nos vários indivíduos da amostra, sendo a frequência do par 21 ligeiramente maior. O comportamento associativo dos cromossomos marcadores, quando comparado ao de seus homólogos, não se mostrou diferente nos vários indivíduos da amostra. Os cromossomos D e Gs+ associaram-se preferencialmente (0,05 < P < 0,1), o que sugere a existência de cistrons para ARN ribossômico na região dos satélites dos acrocêntricos

Reciprocal recurrent selection effects on the genetic structure of tropical maize populations assessed at microsatellite loci

A modified reciprocal recurrent selection (RRS) method, which employed one cycle of high-intensity selection, was applied to two tropical maize (Zea mays L.) populations, BR-105 and BR-106, originating the improved synthetics IG-3 and IG-4, respectively. In the present study the effects of this kind of selection on the genetic structure of these populations and their synthetics were investigated at 30 microsatellite (SSR) loci. A total of 125 alleles were revealed. A reduction in the number of alleles was observed after selection, as well as changes in allele frequencies. In nearly 13% (BR-105) and 7% (BR-106) of the loci evaluated, the changes in allele frequencies were not explained, exclusively due to the effects of genetic drift. The effective population sizes estimated for the synthetics using 30 SSR loci were similar to those theoretically expected after selection. The genetic differentiation (G ST) between the synthetics increased to 77% compared with the original populations. The estimated R ST values, a genetic differentiation measure proper for microsatellite data, were similar to those obtained for G ST. Despite the high level of selection applied, the total gene diversity found in the synthetics allows them to be used in a new RRS cycle.355364Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Anatomical studies of in vitro organogenesis induced in leaf-derived explants of passionfruit

Com o objetivo de estudar a organogênese in vitro em Passiflora edulis Sims f. flavicarpa Deg., o maracujá-amarelo, explantes derivados de folha foram cultivados em meio contendo NAA ou BAP, no escuro e na presença de luz. Foram descritos os eventos histológicos que levam à formação de novo de órgãos. Concluiu-se que o escuro induz a rizogênese, na presença de NAA, enquanto a regeneração de brotos é estimulada pela luz e BAP. Esta condição é recomendada para micropropagar o maracujá uma vez que vários brotos adventícios são formados a partir de meristemóides de origem parenquimática.With the aim of studying the organogenesis in vitro in Passiflora edulis Sims f. flavicarpa Deg., the passionfruit, leaf-derived explants were cultured on media containing NAA or BAP and incubated either in continuous darkness or in light. The histological events leading to de novo organ formation were evaluated. Darkness induces rhizogenesis in the presence of NAA, whereas direct shoot regeneration is stimulated by light and BAP. This latter condition is recommended for passionfruit micropropagation as several adventitious shoot buds were formed from meristemoids of parenchymal origin

Determination of taxonomic relationships among Brazilian taxa of Stylosanthes Sw., Leguminosae, using RAPD markers

A potencialidade dos RAPDs para estudos taxonômicos foi investigada em seis táxons de Stylosanthes Sw. Baseando-se na presença/ausência das bandas de RAPD, similaridades genéticas foram calculadas e um dendrograma construído de acordo com o método UPGMA. Dois grupos foram claramente diferenciados: um, representado por uma espécie anual (S. humilis), e outro, pelos táxons pertencentes ao complexo S. guianensis. Entre os táxons deste último grupo, os RAPDs foram capazes de discriminar S. gracilis, a qual estaria sob processo de divergência evolutiva.The potential use of RAPDs for taxonomic studies was investigated in six Stylosanthes Sw. taxa. Based on the presence/absence of RAPDs bands, genetic similarities were evaluated and a dendrogram was built according to the UPGMA procedure. Two groups were clearly differentiated, one represented by an annual species (S. humilis) and another by the controversial taxa belonging to the S. guianensis complex. Among taxa of the latter group RAPDs have proven useful for discriminating S. gracilis, that should be under a process of evolutionary divergence

A novel linkage map of sugarcane with evidence for clustering of retrotransposon-based markers

The development of sugarcane as a sustainable crop has unlimited applications. The crop is one of the most economically viable for renewable energy production, and CO2 balance. Linkage maps are valuable tools for understanding genetic and genomic organization, particularly in sugarcane due to its complex polyploid genome of multispecific origins. The overall objective of our study was to construct a novel sugarcane linkage map, compiling AFLP and EST-SSR markers, and to generate data on the distribution of markers anchored to sequences of scIvana_1, a complete sugarcane transposable element, and member of the Copia superfamily. The mapping population parents (‘IAC66-6’ and ‘TUC71-7’) contributed equally to polymorphisms, independent of marker type, and generated markers that were distributed into nearly the same number of co-segregation groups (or CGs). Bi-parentally inherited alleles provided the integration of 19 CGs. The marker number per CG ranged from two to 39. The total map length was 4,843.19 cM, with a marker density of 8.87 cM. Markers were assembled into 92 CGs that ranged in length from 1.14 to 404.72 cM, with an estimated average length of 52.64 cM. The greatest distance between two adjacent markers was 48.25 cM. The scIvana_1-based markers (56) were positioned on 21 CGs, but were not regularly distributed. Interestingly, the distance between adjacent scIvana_1-based markers was less than 5 cM, and was observed on five CGs, suggesting a clustered organization. Results indicated the use of a NBS-profiling technique was efficient to develop retrotransposon-based markers in sugarcane. The simultaneous maximum-likelihood estimates of linkage and linkage phase based strategies confirmed the suitability of its approach to estimate linkage, and construct the linkage map. Interestingly, using our genetic data it was possible to calculate the number of retrotransposon scIvana_1 (~60) copies in the sugarcane genome, confirming previously reported molecular results. In addition, this research possibly will have indirect implications in crop economics e.g., productivity enhancement via QTL studies, as the mapping population parents differ in response to an important fungal disease13CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão temnão tem2010/51708-

Extension of the core map of common bean with EST-SSR, RGA, AFLP, and putative functional markers

Microsatellites and gene-derived markers are still underrepresented in the core molecular linkage map of common bean compared to other types of markers. In order to increase the density of the core map, a set of new markers were developed and mapped onto the RIL population derived from the ‘BAT93’ × ‘Jalo EEP558’ cross. The EST-SSR markers were first characterized using a set of 24 bean inbred lines. On average, the polymorphism information content was 0.40 and the mean number of alleles per locus was 2.7. In addition, AFLP and RGA markers based on the NBS-profiling method were developed and a subset of the mapped RGA was sequenced. With the integration of 282 new markers into the common bean core map, we were able to place markers with putative known function in some existing gaps including regions with QTL for resistance to anthracnose and rust. The distribution of the markers over 11 linkage groups is discussed and a newer version of the common bean core linkage map is proposed