Research Interests

- Meiosis in scorpions (Arachnida): model to understand the evolution in species with achiasmate chromosomes.
The order Scorpiones presents a high diversity of species and has revealed peculiar and intriguing chromosomal features, which can constitute model to understand the chromosome evolution in other groups of animals. This proposition is based on the fact that the examined species exhibited: 1) high interspecific and intraspecific variability in relation to diploid number and chromosome behavior during meiosis, permitting the genetic characterization of different populations; 2) presence of holocentric or monocentric chromosomes, making it possible to study the evolutionary differentiation between these two types of chromosomes; 3) synaptic and achiasmate meiosis, which permits to investigate the events responsible for the genetic variability in scorpions; 4) high incidence of chromosome rearrangements of the translocation or fission/fusion type, which can occur due to chromosome molecular organization and/or population structure of the scorpions. Taking into account these data, the aim of this project is to establish the mechanisms related with intra and interspecific variability of diploid number and understand the evolutionary meaning of the high frequency of chromosome rearrangement and presence of synaptic and achiasmate mode of meiosis. The mitotic and meiotic chromosomes of Scorpiones species from Brazilian fauna are been examined, using techniques of standard and differential staining (C-band, silver impregnation, base-specific fluorochrome staining), molecular cytogenetic (FISH with rDNA and telomere probe), ultrastructural analyses (cellular microspreading or surface spreading) and immunostaining (employing antibodies that recognized certain synaptonemal complex constituents, nodule of recombination, and histone modifications).

- Chromosome evolution in Coleoptera
The order Coleoptera has around 360.000 described species, presents a world-wide distribution, and corresponds to the largest group within the class Insecta. In contrast with this diversity of species, the cytogenetic data in Coleoptera are scarce, taking into account that less than 1% of the beetles were examined and the majority of species was not studied with differential staining techniques that highlight specific chromosomal regions. The cytogenetic investigation in different families of beetles has the aim of establishing the main mechanisms of chromosome evolution among related species, considering that the analyzed species have shown interesting karyotype characteristics, e.g., great variability of chromosome number due to the alterations in the karyotype 2n=18+Xyp, which has been presumed to be ancestral for Polyphaga, and great diversity in the types of sex chromosome systems, which was originated by rearrangements involving the autosomes and sex chromosomes. The chromosome characterization of the Coleoptera species has been accomplished through the analyses of mitotic and meiotic cells, submitted to conventional, differential and molecular techniques.

Papers

- Stavale LM; Schneider MC; Brescovit AD; Cella DM. Chromosomal characteristics and karyotype evolution of Oxyopidae spiders (Araneae, Entelegynae). Genetics and Molecular Research, 10: 752-763, 2011.

- Schneider MC; Cella DM. Karyotype conservation in 2 populations of the parthenogenetic scorpion Tityus serrulatus (Buthidae): rDNA and its associated heterochromatin are concentrated on only one chromosome. Journal of Heredity, 101: 491-496, 2010.

- Schneider MC; Zacaro AA; Ferreira A; Cella DM. Karyotype plasticity in crickets: numerical, morphological, and nucleolar organizer region distribution pattern of Anurogryllus sp. Journal of Insect Science, 10: 87, 2010.

- Stavale LM; Schneider MC; Araújo D; Brescovit AD; Cella DM. Chromosomes of Theridiidae spiders (Entelegynae): interspecific karyotype diversity in Argyrodes and diploid number intraspecific variability in Nesticodes rufipes. Genetics and Molecular Biology, 33: 1-6, 2010.

- Schneider MC; Zacaro AA; Pinto-da-Rocha R; Candido DM; Cella DM. Complex meiotic configuration of the holocentric chromosomes: the intriguing case of the scorpion Tityus bahiensis. Chromosome Research, 17: 883-898, 2009.

- Schneider MC; Zacaro AA; Pinto-da-Rocha R; Candido DM; Cella DM. A comparative cytogenetic analysis of two Bothriuridae species and overview of the chromosome data of Scorpiones. Journal of Heredity, 100: 545-555, 2009.

- Gross MC; Feldberg E; Cella DM; Schneider MC; Schneider CH; Porto J; Martins C. Intriguing evidence of translocations in Discus fish (Symphysodon, Cichlidae) and a report of the largest meiotic chromosomal chain observed in vertebrates. Heredity, 102: 435-441, 2009.

- Schneider MC; Zacaro AA; Oliveira RM; Gnaspini P; Cella DM. Conventional and ultrastructural analyses of the chromosomes of Discocyrtus pectinifemur (Opiliones, Laniatores, (Gonyleptidae). Journal of Zoological Systematics and Evolutionary Research, 47: 203-207, 2008.

- Ramalho MO; Araújo D; Schneider MC; Brescovit AD; Cella DM. Mesabolivar brasiliensis (Moenkhaus 1898) and Mesabolivar cyaneotaeniatus (Keyserling 1891) (Araneomorphae, Pholcidae): close relationship reinforced by cytogenetic analyses. Journal of Arachnology, 36: 01-04, 2008.

- Schneider MC; Rosa SP; Almeida MC; Costa C; Cella DM. Chromosomal similarities and differences among four Neotropical Elateridae (Conoderini and Pyrophorini) and other related species, with comments on the NORs pattern in Coleoptera. Journal of Zoological Systematics and Evolutionary Research, 45: 308-316, 2007.

- Schneider MC; Rosa SP; Almeida MC; Costa C; Cella DM. Strategies of karyotype differentiation in Elateridae (Coleoptera, Polyphaga). Micron (Oxford), 38: 590-598, 2007.

- Schneider MC; Carraro BP; Cella DM; Matiello RR; Artoni RF; Almeida MC. Astylus variegatus (Coleoptera, Melyridae): cytogenetic study of a population exposed to agrochemical products. Genetics and Molecular Biology, 30: 640-645, 2007.

- Dias CM; Schneider MC; Rosa SP; Costa C; Cella DM. The first cytogenetic report of fireflies (Coleoptera, Lampyridae) from Brazilian fauna. Acta Zoologica (Stockholm), 88: 309-316, 2007.

- Schneider MC; Almeida MC; Rosa SP; Costa C; Cella DM. Evolutionary chromosomal differentiation among four species of Conoderus Eschscholts, 1829 (Coleoptera, Elateridae, Agrypninae, Conoderini) detected by standard staining, C-banding, silver nitrate impregnation, and CMA3/DA/DAPI staining. Genetica (The Hague), 128: 333-346, 2006.

- Schneider MC; Artoni RF; Almeida MC. Cytogenetic analysis of 3 populations of Diabrotica speciosa (Chrysomelidae, Galerucinae): constitutive heterochromatin and nucleolus organizer regions. Cytologia, 67: 281-287, 2002.

Book Chapters

- SCHNEIDER MC; CELLA DM. Citogenética de insetos de importância para entomologia forense: Coleoptera e Diptera. In: LEONARDO GOMES (Org.). Entomologia forense: novas tendências e tecnologias nas ciências criminais. 1a ed. Rio de Janeiro: Technical Books, 321-361, 2010.

Cytogenetics
Events and mechanisms of meiosis: an evolutionary approach
Evolution
Genetics