title: First cytogenetic characterization of a species of the arboreal ant genus Azteca Forel, 1978 (Dolichoderinae, Formicidae).
abstract: In this paper we present, for the first time, a detailed karyotype characterization of a species of the genus Azteca (Dolichoderinae, Formicidae). Cerebral ganglia from Azteca trigona Emery, 1893 were excised and submitted to colchicine hypotonic solution and chromosomal preparations were analyzed through conventional staining with Giemsa, C-banding, silver nitrate staining (AgNO3) and sequential base-specific fluorochromes. The analysis shows that Azteca trigona has a diploid number of 28 chromosomes. The karyotype consists of five metacentric pairs, seven acrocentric pairs and two pseudo-acrocentric pairs, which represents a karyotype formula 2K= 10M + 14A + 4A(M) and a diploid number of the arms 2AN = 38. The analysis of heterochromatin distribution revealed a positive block on distal region of the short arm of fourth metacentric pair, which was coincident with Ag-NOR band and CMA3 fluorochrome staining, meaning that rDNA sequences are interspaced by GC-rich base pairs sequences. The C-banding also marked short arms of other chromosomes, indicating centric fissions followed by heterochromatin growth. The karyotype analysis of Azteca trigona allowed the identification of cytogenetic markers that will be helpful in a difficult taxonomic group as Azteca and discussion about evolutionary aspects of the genome organization.
authors.affiliation: Programa de Pós-graduação em Genética e Melhoramento, edifício Arthur Bernardes, subsolo sala 12, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil ; Departamento de Biologia Geral, Av. Peter Henry Rolfs s/n, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Danon Clemes
authors.initials: DC
authors.lastname: Cardoso
authors.forename: Maykon Passos
authors.initials: MP
authors.lastname: Cristiano
authors.forename: Luísa Antônia Campos
authors.initials: LA
authors.lastname: Barros
authors.forename: Denilce Meneses
authors.initials: DM
authors.lastname: Lopes
authors.forename: Silvia das Graças
authors.initials: Sd
authors.lastname: Pompolo
keywords: Azteca trigona; ants; chromosome banding; chromosome number; karyotype