Araya-Jaime Cristian Andrés, Silva Duílio Mazzoni Zerbinato de Andrade, da Silva Luís Ricardo Ribeiro, do Nascimento Cristiano Neves, Oliveira Claudio, Foresti Fausto
Instituto de Investigación Multidisciplinar en Ciencia y Tecnología, Universidad de La Serena, La Serena, Chile.
Departamento de Biología, Universidad de La Serena, La Serena, Chile.
Comp Cytogenet. 2022 May 5;16(2):127-142. doi: 10.3897/CompCytogen.v16i2.72190. eCollection 2022.
The genus Jordan et Evermann,1896 includes electric fishes endemic to the Neotropical region with extensive karyotype variability and occurrence of different sex chromosome systems, however, cytogenetic studies within this group are restricted to few species. Here, we describe the karyotypes of (Schreiner et Miranda Ribeiro, 1903) and (Reinhardt, 1852) and the chromosomal locations of 5S and 18S rDNAs (ribosomal RNA genes) and U2 snDNA (small nuclear RNA gene). Among them, 18S rDNA sites were situated in only one chromosomal pair in both species, and co-localized with 5S rDNA in . On the other hand, 5S rDNA and U2 snRNA sites were observed on several chromosomes, with variation in the number of sites between species under study. These two repetitive DNAs were observed co-localized in one chromosomal pair in and in four pairs in . Our study shows a new case of association of these two types of repetitive DNA in the genome of Gymnotiformes.
乔丹氏电鳗属（Jordan et Evermann，1896）包括新热带区特有的电鱼，其核型具有广泛变异性且存在不同的性染色体系统，然而，该类群内的细胞遗传学研究仅限于少数物种。在此，我们描述了线翎电鳗（Schreiner et Miranda Ribeiro，1903）和艾氏电鳗（Reinhardt，1852）的核型以及5S和18S rDNA（核糖体RNA基因）和U2 snDNA（小核RNA基因）的染色体定位。其中，18S rDNA位点在两个物种中均仅位于一对染色体上，并且在艾氏电鳗中与5S rDNA共定位。另一方面，在几条染色体上观察到了5S rDNA和U2 snRNA位点，在所研究的物种之间位点数量存在差异。在线翎电鳗中这两种重复DNA在一对染色体上共定位，而在艾氏电鳗中在四对染色体上共定位。我们的研究显示了裸背电鳗目基因组中这两种重复DNA关联的一个新实例。
