Cytogenetic Mapping of 5S and 18S rRNAs and H3 Histone Genes in 4 Ancient Proscopiidae Grasshopper Species: Contribution to Understanding the Evolutionary Dynamics of Multigene Families

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

Molecular cytogenetic study of heterochromatin in Hisonotus leucofrenatus (Teleostei, Loricariidae, Hypoptopomatinae)

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

Chromosomal location of heterochromatin and 45S rDNA sites in four South American triatomines (Heteroptera: Reduviidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cytogenetical and cytotaxonomical analysis of some Brazilian species of Eleocharis (Cyperaceae)

Karyotype analysis of 21 samples of 11 species of Eleocharis ( Cyperaceae) from 10 localities in Brazil, showed the presence of chromosomes without primary constrictions and parallel movement of chromatids at metaphase-anaphase transition. Only the terminal nucleolar constrictions ( satellites) were visualised. The chromosome numbers varied from 2n=6 in E. subarticulata to 2n=54 in E. acutangula, but the chromosome basic number x=5 was confirmed. Generally, C-CMA(3)(+) bands appear mostly in the extremities of the chromosomes, associated to NOR, and interstitial C-CMA(3) bands were found only in E. geniculata and E. acutangula. C-DAPI(+) bands were not found. Fluorescence in situ hybridisation ( FISH) with the 45S rDNA probe was performed in five species. The results showed from four to eight hybridisation signals, always terminal. The analysed species include representatives of the following three subgenera of Eleocharis that occur in Brazil: Limnochloa, Scirpidium and Eleocharis. Species from the subgenus Limnochloa have small and numerous chromosomes. The remaining species, belonging to subgenera Eleocharis and Scirpidium, possess fewer and larger chromosomes. In subgenus Eleocharis, karyotypes of the section Eleocharis were differentiated by symploidy, agmatoploidy and polyploidy, whereas species of the section Eleogenus were all polyploids. Polyploidy seems to be the most frequent event in the karyotype differentiation in Eleocharis, but changes in the chromosome size and repetitive DNA sites were also observed.

Intrachromosomal distribution of telomeric repeats in Eumops glaucinus and eumops perotis (Molossidae, Chiroptera)

The location of chromosomal telomeric repeats (TTAGGG)(n) was investigated in two species of the Molossidae family, Eumops glaucinus and Eumops perotis. The diploid chromosome number (2n) is 40 in E. glaucinus and 48 in E. perotis and the fundamental numbers (FN) are 64 and 58, respectively. It has been suggested that the E. glaucinus karyotype has evolved from the E. perotis karyotype through Robertsonian fusion events. In the present study, the telomeric sequences were detected at the termini of chromosomes in both species. In addition, E. glaucinus also displayed telomeric repeats in centromeric and pericentromeric regions in almost all biarmed chromosomes. Conversely, in E. perotis pericentromeric signals were only observed in two biarmed chromosomes. In both E. glaucinus and E. perotis, such telomeric sequences were observed as part of the heterochromatin. The interstitial sites of telomeric sequences suggest that they are remnants of telomeres of ancestral chromosomes that participated in the fusion event.

Karyotype analysis of seven species of the tribe lophiohylini (Hylinae, Hylidae, Anura), with conventional and molecular cytogenetic techniques

Few species of the tribe Lophiohylini have been karyotyped so far, and earlier analyses were performed mainly with standard staining. Based on the analysis of seven species with use of routine banding and molecular cytogenetic techniques, the karyotypes were compared and the cytogenetic data were evaluated in the light of the current phylogenies. A karyotype with 2n = 24 and NOR in the chromosome 10 detected by Ag-impregnation and FISH with an rDNA probe was shared by Aparasphenodon bokermanni Miranda-Ribeiro, 1920, Itapotihyla langsdorffii (Duméril and Bibron, 1841), Trachycephalus sp., T. mesophaeus (Hensel, 1867), and T. typhonius (Linnaeus, 1758). Phyllodytes edelmoi Peixoto, Caramaschi et Freire, 2003 and P. luteolus (Wied-Neuwied, 1824) had reduced the diploid number from 2n = 24 to 2n = 22 with one of the small-sized pairs clearly missing, and NOR in the large chromosome 2, but the karyotypes were distinct regarding the morphology of chromosome pairs 4 and 6. Based on the cytogenetic and phylogenetic data, it was presumed that the chromosome evolution occurred from an ancestral type with 2n = 24, in which a small chromosome had been translocated to one or more unidentified chromosomes. Whichever hypothesis is more probable, other rearrangements should have occurred later, to explain the karyotype differences between the two species of Phyllodytes Wagler, 1830. The majority of the species presented a small amount of centromeric C-banded heterochromatin and these regions were GC-rich. The FISH technique using a telomeric probe identified the chromosome ends and possibly (TTAGGG)n-like sequences in the repetitive DNA out of the telomeres in I. langsdorffii and P. edelmoi. The data herein obtained represent an important contribution for characterizing the karyotype variability within the tribe Lophiohylini scarcely analysed so far. © Simone Lilian Gruber et al.

Karyotypic conservatism in five species of Prochilodus (Characiformes, Prochilodontidae) disclosed by cytogenetic markers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chromosomal diversification of diploid number, heterochromatin and rDNAs in two species of Phanaeus beetles (Scarabaeidae, Scarabaeinae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Citogenética comparativa de peixes da família Cichlidae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dinâmica evolutiva de DNAs repetitivos com ênfase em espécies da tribo Phanaeini

Pós-graduação em Ciências Biológicas (Genética) - IBB

Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae)

Espécies de Eigenmannia estão amplamente distribuídas na região Neotropical, com oito espécies válidas atualmente reconhecidas. Populações de Eigenmannia de três localidades do leste da Amazônia foram investigadas usando técnicas citogenéticas e morfológicas, revelando dois táxons designados aqui comoEigenmannia sp. "A" e Eigenmannia sp. "B". As espécies diferem em três caracteres morfométricos, dois merísticos e um osteológico. Eigenmannia sp. "A" apresenta 2n = 34 (22 m/sm+12st/a) e Eigenmannia sp. "B" apresenta 2n = 38 (14 m/sm+24st/a) e cromossomos sexuais de diferenciação simples, do tipo XX/XY. Em ambas espécies a Heterocromatina Constitutiva (HC) rica em bases A-T está distribuída na região centromérica de todos os cromossomos. Eigenmannia sp. "B" também apresenta blocos de HC na região intersticial dos pares cromossômicos 8, 9 e X que coraram positivamente para CMA₃, indicando regiões ricas em G-C. A NOR está localizada no braço curto do par 17 em Eigenmannia sp. "A" e no braço curto do par 14 em Eigenmannia sp. "B". FISH com sondas de rDNA hibridizaram em regiões de tamanhos diferentes entre os homólogos, sugerindo heteromorfismo. A diferenciação do cromossomo X em Eigenmannia sp. "B" pode ser o resultado de amplificação de sequências repetitivas de DNA.

Bandamento em cromossomos de peixes: discussão sobre o conceito de compartimentalização cromossômica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Origens dos cromossomos B em espécies de Characidium (Characiformes, Crenuchidae) baseada em pintura cromossômica, sequências de rDNA e histonas

Pós-graduação em Ciências Biológicas (Genética) - IBB

Estrutura molecular e citogenética de cromossomos B em Astyanax paranae (Characiformes, Characidae)

Pós-graduação em Ciências Biológicas (Genética) - IBB

Scattered organization of the histone multigene family and transposable elements in Synbranchus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)