Piscor Diovani, Parise-Maltempi Patricia Pasquali
Instituto de Biociências, Departamento de Biologia, Laboratório de Citogenética, Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Av. 24A, 1515, CEP: 13506-900, Rio Claro, SP, Brazil.
Comp Cytogenet. 2015 Jul 3;9(3):325-33. doi: 10.3897/CompCytogen.v9i3.5224. eCollection 2015.
The Hyphessobrycon are allocated in the incertae sedis group of the Characidae family, one of the genera with more species of the group. The chromosomes of some species of Hyphessobrycon are known, and the diploid number most common for genus is 2n = 50 chromosomes. The aims of this study were to examine the karyotype macrostructure in the Hyphessobryconeques Steindachner, 1882, and show a new origin hypothesis for B chromosomes. The diploid number observed for Hyphessobryconeques was 2n = 52 chromosomes, and a karyotype formulae of 12m + 18sm + 8st + 14a, with FN (fundamental number) = 90 for both sexes. Only two females showed one B chromosome. The heterochromatin was observed mainly on centromeric regions, and in the long arm of the B chromosome. In this paper, the relationship of the B chromosome of Hyphessobryconeques with an occasional chromosome rearrangement was discussed.
魮脂鲤属被归类于脂鲤科的分类地位不确定类群，是该类群中物种较多的属之一。魮脂鲤属一些物种的染色体情况已知，该属最常见的二倍体数目是2n = 50条染色体。本研究的目的是检测1882年施泰因达赫纳命名的似魮脂鲤的核型宏观结构，并提出B染色体起源的新假说。似魮脂鲤的观察到的二倍体数目为2n = 52条染色体，核型公式为12m + 18sm + 8st + 14a，两性的臂数（FN）均为90。只有两只雌性显示有一条B染色体。异染色质主要出现在着丝粒区域以及B染色体的长臂上。本文讨论了似魮脂鲤B染色体与偶尔发生的染色体重排之间的关系。
