title: Cytogenetic data on the threatened leafcutter ant Atta robusta Borgmeier, 1939 (Formicidae: Myrmicinae: Attini).
abstract: The 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.
authors: Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil; Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil. Electronic address: luufv@yahoo.com.br.
authors: Luísa Antônia Campos
authors: LA
authors: Barros
authors: Programa de Pós-graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil; Universidade Federal do Amapá, Campus Binacional, Oiapoque, AP 68980-000, Brazil.
authors: Hilton Jeferson Alves Cardoso de
authors: HJ
authors: Aguiar
authors: Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil.
authors: Gisele Amaro
authors: GA
authors: Teixeira
authors: Laboratório de Mirmecologia, CEPEC/CEPLAC, Itabuna, BA CP 7, 45600-000, Brazil; Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, BA 45650-000, Brazil.
authors: Cléa Dos Santos Ferreira
authors: Cdos S
authors: Mariano
authors: Departamento de Ciências Agrárias e Ambientais, Universidade Federal do Espírito Santo, ES, Brazil.
authors: Marcos da Cunha
authors: Mda C
authors: Teixeira
authors: Laboratório de Mirmecologia, CEPEC/CEPLAC, Itabuna, BA CP 7, 45600-000, Brazil; Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, BA 45650-000, Brazil.
authors: Jacques Hubert Charles
authors: JH
authors: Delabie
authors: Laboratório de Citogenética de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil.
authors: Silvia das Graças
authors: Sd
authors: Pompolo
mesh_terms: D000818:Animals; D001000:Ants / Q000235:genetics*; D001938:Brazil; D002871:Chromosome Banding; D059006:Chromosomes, Insect / Q000235:genetics / Q000648:ultrastructure; D003247:Conservation of Natural Resources; D004275:DNA, Ribosomal / Q000235:genetics; D004171:Diploidy; D056727:Endangered Species; D017344:Genes, Insect; D006570:Heterochromatin / Q000648:ultrastructure; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D006570:Heterochromatin; D012337:RNA, Ribosomal, 18S
keywords: Banding techniques; Caryotype; Conservation; FISH; Karyotype; Littoral; Restinga; Techniques de marcation