Cytogenetic studies in Hasemania crenuchoides (Characiformes: Characidae) and molecular investigations into kinship relationships of the genus
2018
Duarte, Matheus Almeida | Giugliano, Lilian Gimenes | de Aquino, Pedro De Podestà Uchôa | Grisolia, Cesar Koppe | Milhomem-Paixão, Susana Suely Rodrigues
The genus Hasemania is considered incertae sedis from the family Characidae which possesses nine fish species. Hasemania crenuchoides is endemic to the Federal District of Brazil and is under threat of extinction. The objective of this work was to characterize the Hasemania crenuchoides karyotype and investigate phylogenetic relationships using the 5ʹ region of the COI gene. Our results showed a chromosome number of 2n = 50, with a fundamental number equal to 82 and a karyotype formula of 32m/sm+ 18st/a. C banding evidenced that constitutive heterochromatin is not only present in pericentromeric regions, but also in telomeric and interstitial regions. Ag-NOR marking occurred in the short arm of pair 6. DAPI staining revealed that few bands were rich in A/T. The diploid number observed is in accordance with previous findings in Characidae, including the presence of a long metacentric pair, and is considered a plesiomorphic character. Based on the literature, together with cytogenetic and molecular data, it is suggested that Hasemania is possibly not monophyletic, composed of two groups: (1) a basal group with H. hanseni and H. nana; and (2) a derived group with H. crenuchoides, H. kalunga, and H. uberaba. Therefore, the molecular and cytogenetic data presented may contribute to understanding phylogenetic relationships within the family.
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