Kantek Daniel Luis Zanella, Moreira Peres Wellington Adriano, Moreira-Filho Orlando
Taiamã Ecological Station, Chico Mendes Biodiversity Conservation Institute, Mato Grosso, Brazil.
Environmental Protection Area Meanders of the Araguaia river, Chico Mendes Biodiversity Conservation Institute, Mato Grosso, Brazil.
Comp Cytogenet. 2015 Feb 5;9(1):17-29. doi: 10.3897/CompCytogen.v9i1.8488. eCollection 2015.
The catfish family Heptapteridae (order Siluriformes) is endemic to the Neotropics and is one of the most common of the fish families in small bodies of water. Although over 200 species have been identified in this family, very few have been characterized cytogenetically. Here, we analyze the chromosome genomes of four species of Heptapteridae: Cetopsorhamdiaiheringi (Schubart & Gomes, 1959), 2n = 58, comprising 28 metacentric (m) + 26 submetacentric (sm) + 4 subtelomeric (st) chromosomes; Pimelodellavittata (Lütken, 1874), 2n = 46, comprising 16m + 22sm + 8st; Rhamdiapropequelen (Quoy & Gaimard, 1824), 2n = 58 comprising 26m + 16sm + 14st + 2 acrocentric; and Rhamdiopsispropemicrocephala (Lütken, 1874), 2n = 56, comprising 12m + 30sm + 14st. The nucleolus organizer regions (NORs) were located in a single chromosome pair in all species. The two species that belonged to the subclade Nemuroglanis, Cetopsorhamdiaiheringi and Rhamdiapropequelen, had a diploid chromosome number of 58 and an interstitial NOR adjacent to a C(+) block located on one of the larger chromosome pairs in the complement. Our results from conventional cytogenetic techniques in combination with FISH using 18S and 5S rDNA probes corroborated the taxonomical hypothesis for the formation of the Nemuroglanis subclade.
鲶鱼科（鲇形目）是新热带界特有的鱼类，是小水体中最常见的鱼类家族之一。尽管该科已鉴定出200多种，但通过细胞遗传学进行特征描述的却很少。在此，我们分析了四种鲶鱼科鱼类的染色体基因组：赫氏新美鲶（Schubart & Gomes，1959），2n = 58，由28条中着丝粒染色体（m）+ 26条亚中着丝粒染色体（sm）+ 4条近端着丝粒染色体（st）组成；带纹原美鲶（Lütken，1874），2n = 46，由16m + 22sm + 8st组成；近奎氏新美鲶（Quoy & Gaimard，1824），2n = 58，由26m + 16sm + 14st + 2条端着丝粒染色体组成；近小头新美鲶（Lütken，1874），2n = 56，由12m + 30sm + 14st组成。所有物种的核仁组织区（NORs）均位于一对染色体上。属于新美鲶亚分支的两个物种，即赫氏新美鲶和近奎氏新美鲶，其二倍体染色体数为58，且在互补的较大染色体对之一上，有一个与C(+)块相邻的中间NOR。我们使用18S和5S rDNA探针，将传统细胞遗传学技术与荧光原位杂交（FISH）相结合的结果，证实了新美鲶亚分支形成的分类学假设。
