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Item Karyotypic description of the stingless bee Melipona quinquefasciata Lepeletier, 1836 (Hymenoptera, Meliponini) with emphasis on the presence of B chromosomes(Comparative Cytogenetics, 2018) Silva, Alexandra Avelar; Rocha, Marla Piumbini; Pompolo, Silvia das Graças; Campos, Lucio Antonio de Oliveira; Tavares, Mara GarciaStingless bees are distributed widely in the tropics, where they are major pollinators of several plant spe- cies. In this study, the karyotype of Melipona quinquefasciata Lepeletier, 1836 was analysed, with emphasis on the presence of B chromosomes. Post-defecating larvae were analysed using Giemsa staining, the C- banding technique, sequential staining with fluorochromes, and FISH. The chromosome number ranged from 2n = 18 to 22 (females) and from n = 9 to 13 (males) due to the presence of 0–4 B chromosomes. This result demonstrates that M. quinquefasciata has the same chromosomal number as other Melipona Illiger, 1806 species. Considering the A complement, heterochromatin was located only in the pericentro- meric region of pair 1. Staining with chromomycin A 3 (CMA 3 ) and labelling with rDNA probe, indicated that this region corresponded to the nucleolus organising region. The B chromosomes of M. quinquefas- ciata could be found in individuals from different localities, they were completely heterochromatic (C- banding) and uniformly stained by 4’,6-diamidino-2-phenylindole (DAPI). Variations in the number of B chromosomes were detected between cells of the same individual, between individuals of the same colony, and between colonies from different localities.Item In vitro responses in Passiflora species with different chromosome numbers, ploidy levels and nuclear 2C values: revisiting and providing new insights(Plant Cell, Tissue and Organ Culture (PCTOC), 2019-03) Carvalho, Carlos Roberto; Clarindo, Wellington Ronildo; Ferreira, Adésio; Praça-Fontes, Milene Miranda; Vieira, Ariane Tonetto; Ferreira, Darley Aparecido Tavares; Leite, Cristiana TorresTissue culture in Passiflora has emerged as a strategy to propagate species with agronomic relevance, which is the main focus of most in vitro studies. Different morphogenic responses have been obtained under the same environmental in vitro conditions, mainly for species of the subgenus Passiflora with distinct 2n chromosome numbers. The aims of this study were to verify and compare the in vitro responses in Passiflora species with distinct 2n chromosome numbers, ploidy levels and nuclear 2C values. Under the same in vitro conditions, only friable calli occurred from mature zygotic embryo explants of Passiflora coriacea (2n = 2x = 12 chromosomes, 2C = 1.00 pg), Passiflora lindeniana (2n = 4x = 24, 2C = 2.42 pg) and Passiflora contracta (2n = 8x = 48, 2C = 4.78 pg). In contrast, plantlets were regenerated from Passiflora foetida (2n = 20, 2C = 1.04 pg) and Passiflora miniata (2n = 18, 2C = 3.40 pg) via indirect organogenesis and indirect somatic embryogenesis, respectively. By now, from mature zygotic embryo explants, de novo shoot organogenesis and somatic embryos have been recovered for Passiflora species with 2n = 18 chromosomes and relative high nuclear 2C value (more than 2C = 2.93 pg—Passiflora cincinata), and only de novo shoot organogenesis for P. foetida with 2n = 20 chromosomes and relative low 2C value (2C = 1.04 pg). Therefore, in a taxonomic and evolutive context, this study showed that the in vitro morphogenic pathways pretty varied between the Passiflora species with distinct karyotype features.Item Flow cytometry and cytogenetic tools in eucalypts: genome size variation × karyotype stability(Tree Genetics & Genomes, 2017-10) Carvalho, Guilherme Mendes Almeida; Carvalho, Carlos Roberto; Soares, Fernanda Aparecida FerrariThe eucalypts comprise a group of woody plants used in commercial forest plantations owing to their high growth rates, adaptability to various ecological conditions and multiple applications. Despite the enormous amount of molecular data available for eucalypts, a basic understanding of the nature of its genome still requires information regarding the DNA amount in the genus. In this work, we estimated the genome size and base composition of 25 eucalypt species. With a comparative karyotype approach, we aimed to identify possible chromosomal alterations correlated with the genome size variation. Classical cytogenetic and genomic in situ hybridization experiments were conducted for this purpose. The studied species showed genome size ranging from 2C = 0.91 (Corymbia intermedia) to 2C = 1.37 pg (Eucalyptus paniculata) and AT/CG ratios varying from AT = 61.3 (Eucalyptus urophylla) to AT = 62.85% (C. intermedia). Comparative karyotype analysis revealed no remarkable differences in chromosome number (2n = 22) or morphology among eucalypt species despite considerable differences in nuclear DNA content. The genome in situ hybridization method did not distinguish non-homologous chromosomal regions of Eucalyptus baileyana and Corymbia citriodora, despite the difference of 0.45 pg between their genome sizes. The results found in the present work corroborate the consideration of small and dispersed DNA changes as the main cause of genome size variation in eucalypts.Item Karyotype revised of Pisum sativum using chromosomal DNA amount(Plant Systematics and Evolution, 2014-08) Carvalho, Carlos Roberto; Fontes, Milene Miranda Praça; Clarindo, Wellington RonildoPisum sativum was one of the first plants for which the mitotic karyotype was recognized and the karyogram assembled. These achievements were required owing to the physical mapping of P. sativum, providing data for evolutionary approaches and breeding programs. In spite of significant advances, precise morphometric characterization of chromosomes and karyogram assembly of P. sativum have become a topical problem. The present study proposes an unambiguous classification for the chromosomes of P. sativum, based on classical cytogenetic rules and chromosomal DNA amount. Cytogenetic procedure yielded mitotic cells showing morphologically preserved and stoichiometrically stained chromosomes. Twelve mitotic cells were selected, and the mean values for total, short- and long-arm lengths and DNA amount were measured for each chromosome. Chromosomal DNA amount fully correlated with total chromosome length, whose value proportionally decreases with the amount of DNA. Considering these data, all seven chromosomes could be unambiguously identified, yielding a new cytogenetic classification for P. sativum chromosomes. Moreover, the chromosome pairs were ordered according to the classical cytogenetic rule for assembly of karyograms. Since P. sativum is considered a model plant, it was possible to correlate the newly outlined karyotype with other cytogenetic data and linkage groups.Item Chromosomal variation and cytogenetics of Plebeia lucii and P. phrynostoma (Hymenoptera: Apidae)(Florida Entomological Society, 2013-12) Godoy, D. C.; Ferreira, R. P.; Lopes, D. M.Plebeia (Hymenoptera: Apidae) is a poorly defined genus and its classification and systematics are controversial. Tools such as cytogenetics may contribute to clarify the relationships among the species. The aim of this study was to characterize the karyotypes of the species Plebeia lucii Moure, 2004 and Plebeia phrynostoma Moure, 2004. For this purpose conventional staining, C-banding and fluorochrome techniques were performed. The same chromosome number (2n = 34) was observed for both species. The karyotypic formula of P. lucii was 2K = 22 AM + 12A. A heteromorphic pair was observed with euchromatic and heterochromatic regions of different sizes on the 2 homologs. The presence of a secondary constriction was observed in this same pair. In P. phrynostoma the karyotypic formula was 2K = 18AM + 10A + 6M and did not show polymorphisms or secondary constrictions. The DAPI fluorochrome marked portions of the heterochromatic arm and the regions close to the centromere in some chromosomes of both species. CMA3 marked the heteromorphic pair in P. lucii and some points in other chromosomes, while it stained 2 pairs of chromosomes in P. phrynostoma. Despite the similarity in chromosome number, these species show variation both in morphology and in composition of chromatin which may reflect a phylogenetic position in different clades.Item Chromosomal variation and cytogenetics variation of Plebeia lucii and P. phrynostoma (Hymenoptera: Apidae)(Florida Entomologist, 2013-12) Godoy, D. C.; Ferreira, R. P.; Lopes, D. M.Plebeia (Hymenoptera: Apidae) is a poorly defined genus and its classification and systematics are controversial. Tools such as cytogenetics may contribute to clarify the relationships among the species. The aim of this study was to characterize the karyotypes of the species Plebeia lucii Moure, 2004 and Plebeia phrynostoma Moure, 2004. For this purpose conventional staining, C-banding and fluorochrome techniques were performed. The same chromosome number (2n = 34) was observed for both species. The karyotypic formula of P. lucii was 2K = 22 AM + 12A. A heteromorphic pair was observed with euchromatic and heterochromatic regions of different sizes on the 2 homologs. The presence of a secondary constriction was observed in this same pair. In P. phrynostoma the karyotypic formula was 2K = 18AM + 10A + 6M and did not show polymorphisms or secondary constrictions. The DAPI fluorochrome marked portions of the heterochromatic arm and the regions close to the centromere in some chromosomes of both species. CMA3 marked the heteromorphic pair in P. lucii and some points in other chromosomes, while it stained 2 pairs of chromosomes in P. phrynostoma. Despite the similarity in chromosome number, these species show variation both in morphology and in composition of chromatin which may reflect a phylogenetic position in different clades.Item Cytogenetic and flow cytometry data expand knowledge of genome evolution in three Coffea species(Plant Systematics and Evolution, 2012-04) Clarindo, Wellington Ronildo; Carvalho, Carlos Roberto; Mendonça, Maria Andréia CorrêaKaryotype and nuclear 2C-value data are considered important in taxonomic and evolutionary approaches in Coffea. Still, new methods are needed to further support such studies, especially to determine the progenitors of Coffea arabica. In this work, new cytogenetic and flow cytometry data were used to compare Coffea arabica, Coffea canephora and Coffea congensis. These data corroborate the hypothesis that C. canephora and C. congensis originated from a single ancestor, whose basic chromosome number was x = 11. In agreement with the observations of other authors, the karyotype and mean 2C-values confirm that C. arabica is a true allotetraploid originating from two diploid Coffea species with similar genomes. Although C. canephora and C. congensis have been considered potential progenitors of C. arabica, karyotype comparison revealed that only one of these species may be parental to C. arabica. These accurate cytogenetic and flow cytometry data contribute to expand our knowledge of the Coffea genome, as well as of possible progenitors of C. arabica.Item Following the track of “Híbrido de Timor” origin by cytogenetic and flow cytometry approaches(Genetic Resources and Crop Evolution, 2013-12) Clarindo, Wellington Ronildo; Carvalho, Carlos Roberto; Caixeta, Eveline Teixeira; Koehler, Andréa DiasThe supposedly first plant of the coffee cultivar “Híbrido de Timor” (HT) was found in 1927, being denoted as HT CIFC 4106. According to different researchers, this plant originated from a natural interspecific hybridation between Coffea arabica (4x = 44) and Coffea canephora (2x = 22). From HT CIFC 4106, other HT accessions were obtained and employed to establish germplasm banks in some countries. As HT has been widely used in Coffea breeding programs, this study aimed to characterize different HT accessions with regard to ploidy, nuclear DNA content and base composition. Based on these data, the ploidy of HT CIFC 4106 was determined, suggesting that this accession is an allotriploid formed from reduced reproductive cell of C. canephora and of C. arabica. All HT CIFC 4106 plants exhibited the same 2C-value, AT% and chromosome number, showing that vegetative propagation has enabled the multiplication and germplasm conservation of this cytotype since 1927. Further five analyzed HT accessions showed distinct nuclear 2C-value and AT%. Since HT CIFC 4106 has been considered the first HT, it is suggested that aneuploid reproductive cells of this HT originated the other plants. Considering that HT accessions are used in the development of C. arabica cultivars, the findings of this study are important for the design of strategies to obtain new cultivars for breeding programs. Moreover, these data represent the first step to understand the origin and genome evolution of the HT.Item Cytogenetic data on the threatened leafcutter ant Atta robusta Borgmeier, 1939 (Formicidae: Myrmicinae: Attini)(Comptes Rendus Biologies, 2015-08-24) Barros, Luı́sa Antônia Campos; Aguiar, Hilton Jeferson Alves Cardoso de; Teixeira, Gisele Amaro; Mariano, Cléa dos Santos Ferreira; Teixeira, Marcos da Cunha; Delabie, Jacques Hubert Charles; Pompolo, Silvia das GraçasThe karyotype of the threatened ant species Atta robusta is described so as to establish the evolutionary relationships of this taxon with other leafcutter ants. Standard Giemsa staining, C-banding, NOR banding, fluorochromes CMA3/DAPI, Hsc-FA technique and Fluorescence in situ Hybridization (FISH) using 18S rDNA probe were conducted on a population from Aracruz, state of Espírito Santo, Brazil, allowing for comparisons with data available on Atta and other fungus-growing ant species. The diploid chromosome number observed for A. robusta was 2n = 22, and the karyotypic formula was 18m + 2sm + 2st. Heterochromatic blocks were observed in the centromeric region of most chromosomes, where one pair of metacentric chromosomes is characterized by a GC-rich heterochromatic band in the interstitial region of its long arm. The detection of 18S rDNA using FISH confirmed the presence of single NOR for A. robusta. This is the first report of rDNA 18S detection using FISH for leafcutter ants. The cytogenetic results of this study confirm the information available for Atta and allow us to confirm the conserved chromosome number, morphology and banding pattern within the genus for the taxa studied to date, which included species from three out of the four groups of Atta indicated by molecular data. The accumulation of cytogenetic data on fungus-growing ants enhances the understanding of the genomic evolutionary patterns of Atta, since it belongs to a group of recent origin between the most well studied ants. Cytogenetic data does not indicate restrictions in relocation or reintroduction in areas where populations were extinct due to the conserved karyotype. This study allows for cytogenetic comparison of A. robusta with other ants of Atta, emphasizing the importance of chromosomal information for species conservation.Item An overview of cytogenetics of the tribe Meliponini (Hymenoptera: Apidae)(Genetica, 2017-03-01) Tavares, Mara Garcia; Lopes, Denilce Meneses; Campos, L. A. O.The present study provides a comprehensive review of cytogenetic data on Meliponini and their chromosomal evolution. The compiled data show that only 104 species of stingless bees, representing 32 of the 54 living genera have been studied cytogenetically and that among these species, it is possible to recognize three main groups with n = 9, 15 and 17, respectively. The first group comprises the species of the genus Melipona, whereas karyotypes with n = 15 and n = 17 have been detected in species from different genera. Karyotypes with n = 17 are the most common among the Meliponini studied to date. Cytogenetic information on Meliponini also shows that although chromosome number, in general, is conserved among species of a certain genus, other aspects, such as chromosome morphology, quantity, distribution and composition of heterochromatin, may vary between them. This reinforces the fact that the variations observed in the karyotypes of different Meliponini groups cannot be explained by a single theory or a single type of structural change. In addition, we present a discussion about how these karyotype variations are related to the phylogenetic relationships among the different genera of this tribe.