Related Experiment Video
Updated: May 14, 2026

Laboratory Protocol for Genetic Gut Content Analyses of Aquatic Macroinvertebrates Using Group-specific rDNA Primers
Published on: October 5, 2017
Chromosomal diversity in Hypostomus (Siluriformes, Loricariidae) with emphasis on physical mapping of 18S and 5S
J B Traldi1, D R Blanco, M R Vicari
1Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brasil. jositraldi@hotmail.com
Abstract:
We examined chromosomes of three species of the genus Hypostomus, in order to contribute to the understanding of the karyotype evolution of this group. Specimens of H. ancistroides and H. nigromaculatus displayed differences in karyotype formulas, distribution and location of heterochromatin and nucleolus organizer regions when compared to other populations of the same species. We made the first cytogenetic characterization of H. tapijara, an endemic species in the Ribeira de Iguape River. These specimens had 2n = 66 chromosomes, while H. ancistroides showed 2n = 68 and H. nigromaculatus 2n = 76 chromosomes. Physical mapping of 18S and 5S rDNA sites of the three species showed simple, multiple and syntenic clusters. Synteny of ribosomal sites was found in H. ancistroides and H. tapijara, and an interspersed pattern between these sites in all chromosomes bearing the synteny was observed. We conclude that the genus Hypostomus has a high chromosome complexity that is accompanied by great morphological variation. It is evident that this group comprises an interesting model for understanding the chromosome evolution of Neotropical ichthyofauna.
Related Concept Videos
Lampbrush Chromosomes
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
Diversity of Protists IV
Evolutionary Relationships through Genome Comparisons
Diversity of Protists II
FISH - Fluorescent In-situ Hybridization
Diversity of Protists III
