AnÃlise citogenÃtica comparativa em gafanhotos das famÃlias acrididae e romaleidae atravÃs de tÃcnicas convencionais e moleculares

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

A comparative cytogenetic analysis was performed between the romaleid species Chromacris nuptialis and C. speciosa in order to detect possible chromosomic markers through C banding, silver nitrate staining, base-especific fluorochromes (CMA3 and DAPI) and FISH using a 45S rDNA probe. Both species have the same karyotype number, 2n=23,X0 and acrocentric chromosomes. Differences were observed in location and amount of constitutive heterochromatin (CH) and nucleolar organizer regions (NORs) location. Chromacris speciosa presents a high CH amount with the blocks located in pericentromeric, telomeric and intersticial regions. The single NORs pair in this species was in the proximal region of M . On the order hand, C. nuptialis has few CH, with small blocks, almost restricted to the pericentromeric regions and the NORs were observed in the pericentromeric region of M . Some individuals from that species showed meiotic irregularities (anaphasic delay and bridges) involving the L bivalent. The use of baseespecific fluorochromes CMA and DAPI revealed diferencial patterns in terms of CH base composition within the species. Comparative analysis was also performed in five gonphocerine species (Rhammatocerus brasiliensis, R. brunneri, R. palustris, R. pictus e Amblytropidia sp.). These species showed a karyotype 2n=23,X0 and acro-telocentric chromosomes. Adicionally, the analysis of NORs by silver nitrate staining and FISH with a 45S rDNA probe revealed the same pair (S ) as a carrier. However, R. brasiliensis showed 45S rDNA multiple sequences located in the pericentromeric regions of M , M and S . The analysis of B chromosome polimorfism in R. brasiliensis and in the romaleid Xyleus angulatus allowed us to identify some aspects about size, picnosis and meiotic behavior in these extra elements, as well as to suggest a probable autosomic origin for these chromosomes in the karyotype of the species based in CH pattern and 45S and 5S rDNA genes location

ASSUNTO(S)

ciencias biologicas grasshoppers heterochromatin gafanhotos karyotype heterocromatina fish fish cariÃtipo

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