High chromosome variability and the presence of multivalent associations in buthid scorpions

In this study, we investigated the mitotic and meiotic chromosomes of 11 Buthidae scorpion species, belonging to three genera (Ananteris, Rhopalurus and Tityus), to obtain detailed knowledge regarding the mechanisms underlying the intraspecific and/or interspecific diversity of chromosome number and the origin of the complex chromosome associations observed during meiosis. The chromosomes of all species did not exhibit a localised centromere region and presented synaptic and achiasmatic behaviour during meiosis I. Spermatogonial and/or oogonial metaphase cells of these buthids showed diploid numbers range from 2n = 6 to 2n = 28. In most species, multivalent chromosome associations were observed in pachytene and postpachytene nuclei. Moreover, intraspecific variability associated with the presence or absence of chromosome chains and the number of chromosomes in the complex meiotic configurations was observed in some species of these three genera. Silver-impregnated cells revealed that the number and location of nucleolar organiser regions (NORs) remained unchanged despite extensive chromosome variation; notably, two NORs located on the terminal or subterminal chromosome regions were commonly observed for all species. C-banded and fluorochrome-stained cells showed that species with conspicuous blocks of heterochromatin exhibited the lowest rate of chromosomal rearrangement. Based on the investigation of mitotic and meiotic cells, we determined that the intraspecific variability occurred as a consequence of fission/fusion-type chromosomal rearrangements in Ananteris and Tityus species and reciprocal translocation in Rhopalurus species. Furthermore, we verified that individuals presenting the same diploid number differ in structural chromosome organisation, giving rise to intraspecific differences of chromosome association in meiotic cells (bivalent-like elements or chromosome chains). © 2013 Springer Science+Business Media Dordrecht.

Interclonal Variations in the Molecular Karyotype of Trypanosoma cruzi: Chromosome Rearrangements in a Single Cell-Derived Clone of the G Strain

Trypanosoma cruzi comprises a pool of populations which are genetically diverse in terms of DNA content, growth and infectivity. Inter- and intra-strain karyotype heterogeneities have been reported, suggesting that chromosomal rearrangements occurred during the evolution of this parasite. Clone D11 is a single-cell-derived clone of the T. cruzi G strain selected by the minimal dilution method and by infecting Vero cells with metacyclic trypomastigotes. Here we report that the karyotype of clone D11 differs from that of the G strain in both number and size of chromosomal bands. Large chromosomal rearrangement was observed in the chromosomes carrying the tubulin loci. However, most of the chromosome length polymorphisms were of small amplitude, and the absence of one band in clone D11 in relation to its reference position in the G strain could be correlated to the presence of a novel band migrating above or below this position. Despite the presence of chromosomal polymorphism, large syntenic groups were conserved between the isolates. The appearance of new chromosomal bands in clone D11 could be explained by chromosome fusion followed by a chromosome break or interchromosomal exchange of large DNA segments. Our results also suggest that telomeric regions are involved in this process. The variant represented by clone D11 could have been induced by the stress of the cloning procedure or could, as has been suggested for Leishmania infantum, have emerged from a multiclonal, mosaic parasite population submitted to frequent DNA amplification/deletion events, leading to a 'mosaic' structure with different individuals having differently sized versions of the same chromosomes. If this is the case, the variant represented by clone D11 would be better adapted to survive the stress induced by cloning, which includes intracellular development in the mammalian cell. Karyotype polymorphism could be part of the T. cruzi arsenal for responding to environmental pressure. © 2013 Lima et al.

Variabilidade genética entre e dentro de subpopulações de ipê-roxo Handroanthus Heptaphyllus (Vell.) Mattos e seu sistema reprodutivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos de variabilidade genética em populações de Chrysoperla externa Hagen, 1861 (Neuroptera: Chrysopidae) do estado de São Paulo, Brasil

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Isolamento e caracterização de microssatélites em Búfalo de rio (Bubulus bubalis) a partir da construção de bibliotecas genômicas parciais com hibridização seletiva

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genética de populações de Prochilodus argenteus e P. costatus do médio São Francisco

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação de marcadores microssatélites genômicos e funcionais associados a parâmetros agroindustriais em cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

Fluxo de pólen e sementes em população isolada de Copaifera langsdorfii Desf. (LEGUMINOSAE - CAESALPINIOIDEAE) em um fragmento florestal localizado em área urbana

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Distância e padrões de dispersão contemporânea de pólen e sistema de reprodução em pequeno fragmento isolado de Copaifera Langsdorfii Desf. (Leguminosae – Caesalpinoideae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso de marcadores microssatélites para estimar parentescos dentro de progênies de polinização aberta de espécies arbóreas dióicas: um estudo de caso de Myracrodruon urundeuva (F.F. & M.F. Allemão)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversidade genética em populações de Myracrodruon urundeuva Fr. All., sob diferentes tipos de perturbação antrópica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Variabilidade genética de população selecionada e teste de paternidade de uma progênie de polinização aberta de Eucalyptus Grandis Hill ex Maiden

Pós-graduação em Ciência Florestal - FCA

Caracterização genética do pintado Pseudoplatystoma corruscans (Siluriformes: Pimelodidae), da Bacia Paraná-Paraguai, por marcadores moleculares do tipo microssatélite

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)