Campos Alber Sousa, Favarato Ramon Marin, Feldberg Eliana
Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva (PPG GCBEv). Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, , Av. André Araújo, 2936, Petrópolis, Manaus, Amazonas, Brazil Instituto Nacional de Pesquisas da Amazônia Manaus Brazil.
Comp Cytogenet. 2020 Jan 15;14(1):27-42. doi: 10.3897/CompCytogen.v14i1.33483. eCollection 2020.
The karyotypes and chromosomal characteristics of three Eigenmann et Kennedy, 1903 species were examined using conventional and molecular protocols. These species had invariably a diploid chromosome number 2n = 50. (Block, 1794) and (Cuvier, 1819) had the karyotype composed of 16 metacentric (m) + 28 submetacentric (sm) + 6 subtelocentric (st) chromosomes while (Schomburgk, 1841) had the karyotype composed of 14m+30sm+6st elements. In this species, differences of the conventional and molecular markers between the populations of Catalão Lake (AM) and of Apeu Stream (PA) were found. Thus the individuals of Pará (Apeu) were named Acestrorhynchus prope microlepis. The distribution of the constitutive heterochromatin blocks was species-specific, with C-positive bands in the centromeric and telomeric regions of a number of different chromosomes, as well as in interstitial sites and completely heterochromatic arms. The phenotypes of nucleolus organizer region (NOR) were simple, i. e. in a terminal position on the arm of pair No. 23 except in , in which it was located on the arm. Fluorescence hybridization (FISH) revealed 18S rDNA sites on one chromosome pair in karyotype of and A. prope microlepis (pair No. 23) and three pairs (Nos. 12, 23, 24) in and (Nos. 8, 23, 24) in ; 5S rDNA sites were detected in one chromosome pair in all three species. The mapping of the telomeric sequences revealed terminal sequences in all the chromosomes, as well as the presence of interstitial telomeric sequences (ITSs) in a number of chromosome pairs. The cytogenetic data recorded in the present study indicate that A. prope microlepis may be an unnamed species.
利用传统和分子技术方案，对1903年命名的三个 Eigenmann et Kennedy 物种的核型和染色体特征进行了研究。这些物种的二倍体染色体数目均为2n = 50。(Block, 1794) 和 (Cuvier, 1819) 的核型由16条中着丝粒染色体（m）+ 28条亚中着丝粒染色体（sm）+ 6条近端着丝粒染色体（st）组成，而 (Schomburgk, 1841) 的核型由14条中着丝粒染色体 + 30条亚中着丝粒染色体 + 6条近端着丝粒染色体组成。在这个物种中，发现了卡塔朗湖（AM）种群和阿佩乌河（PA）种群之间传统和分子标记的差异。因此，帕拉（阿佩乌）的个体被命名为近小鳞无齿脂鲤（Acestrorhynchus prope microlepis）。组成型异染色质块的分布具有物种特异性，在许多不同染色体的着丝粒和端粒区域以及中间位点和完全异染色质臂上有C阳性带。核仁组织区（NOR）的表型简单，即在第23对染色体的 臂的末端位置，除了 ，其位于 臂上。荧光原位杂交（FISH）显示，在近小鳞无齿脂鲤和 的核型中，一对染色体上有18S rDNA位点（第23对），在 和 中为三对（第12、23、24对），在 中为（第8、23、24对）；在所有三个物种的一对染色体中检测到5S rDNA位点。端粒序列的定位揭示了所有染色体中的末端序列，以及许多染色体对中存在的中间端粒序列（ITSs）。本研究记录的细胞遗传学数据表明，近小鳞无齿脂鲤可能是一个未命名的物种。
