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| Stavale,Leila Miguel; Schneider,Marielle Cristina; Araujo,Douglas; Brescovit,Antonio Domingos; Cella,Doralice Maria. |
| Theridiidae is a derived family within the Araneoidea clade. In contrast to closely related groups, the 2n(male) = 20+X1X2 with acro/telocentric chromosomes is the most widespread karyotype among the theridiid spiders. In this work, the cytogenetic analysis of Argyrodes elevatus revealed original chromosome features different from those previously registered for Theridiidae, including the presence of 2n(male) = 20+X with meta/submetacentric chromosomes. Most individuals of Nesticodes rufipes showed family conserved karyotype characteristics. However, one individual had a 2n(male) = 24 due to the presence of an extra chromosome pair, which exhibited regular behavior and reductional segregation during meiosis. After silver staining, mitotic cells exhibited... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome morphology; Cytogenetic; Meiosis; Nucleolar organizer region; Sex chromosome system. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400012 |
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| Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina. |
| In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023 |
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