Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae)

Autor(es)

Silva, Danillo S. ^[1] ; Peixoto, Luiz A. W. ^[2] ; Pieczarka, Julio C. ^[1] ; Wosiacki, Wolmar B. ^[2] ; Ready, Jonathan S. ^[1] ; Nagamachi, Cleusa Y. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Para UFPA, Inst Ciencias Biol, Lab Citogenet, BR-66075900 Belem, Para - Brazil

^[2] Museu Paraense Emilio Goeldi MCT&I, Setor Ictiol, Coordenacao Zool, BR-66077830 Belem, Para - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Neotropical Ichthyology; v. 13, n. 2, p. 297-308, APR-JUN 2015.
• Citações Web of Science: 3

Resumo

Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. "A" and Eigenmannia sp. "B". The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. "A" presents 2n = 34 (22 m/sm+12 st/a) and Eigenmannia sp. "B" presents 2n = 38 (14 m/sm+24st/a) and simple differentiated sex chromosomes of the type XX/XY. In both species the Constitutive Heterochromatin (CH) rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. "B" also presents CH blocks in the interstitial region of chromosome pairs 8, 9 and X which are positively stained with CMA3, indicating G-C rich regions. The NOR is located on the short arm of chromosome pair 17 of Eigenmannia sp. "A" and on the short arm of pair 14 of Eigenmannia sp. "B". FISH with rDNA probes hybridized to different-sized regions between homologs, suggesting heteromorphism. The differentiation of the X chromosome in Eigenmannia sp. "B" could be the result of amplification of repetitive DNA sequences. (AU)

• Processo FAPESP: 13/09926-3 - Implicações filogenéticas e taxonômicas na miologia facial comparada de Gymnotiformes e Siluriformes
• Beneficiário: Luiz Antonio Wanderley Peixoto
• Modalidade de apoio: Bolsas no Brasil - Doutorado