Related Experiment Video
Updated: Jun 21, 2026

High-throughput Physical Mapping of Chromosomes using Automated in situ Hybridization
Published on: June 28, 2012
Comparative chromosome mapping of repetitive sequences. Implications for genomic evolution in the fish, Hoplias
Marcelo B Cioffi1, Cesar Martins, Luiz A C Bertollo
1Universidade Federal de São Carlos, Departamento de Genética e Evolução, São Carlos, SP, Brazil. mbello.ufscar@gmail.com
Background:
Seven karyomorphs of the fish, Hoplias malabaricus (A-G) were previously included in two major groups, Group I (A, B, C, D) and Group II (E, F, G), based on their similar karyotype structure. In this paper, karyomorphs from Group I were analyzed by means of distinct chromosomal markers, including silver-stained nucleolar organizer regions (Ag-NORs) and chromosomal location of repetitive sequences (18S and 5S rDNA, and satellite 5SHindIII-DNA), through fluorescence in situ hybridization (FISH), in order to evaluate the evolutionary relationships among them.
Results:
The results showed that several chromosomal markers had conserved location in the four karyomorphs. In addition, some other markers were only conserved in corresponding chromosomes of karyomorphs A-B and C-D. These data therefore reinforced and confirmed the proposed grouping of karyomorphs A-D in Group I and highlight a closer relationship between karyomorphs A-B and C-D. Moreover, the mapping pattern of some markers on some autosomes and on the chromosomes of the XY and X1X2Y systems provided new evidence concerning the possible origin of the sex chromosomes.
Conclusion:
The in situ investigation of repetitive DNA sequences adds new informative characters useful in comparative genomics at chromosomal level and provides insights into the evolutionary relationships among Hoplias malabaricus karyomorphs.
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...
Cis-regulatory Sequences
Evolutionary Relationships through Genome Comparisons
Overview of Transposition and Recombination
Multi-species Conserved Sequences
Although the genome of each species varies greatly from each other, a few sequences are highly conserved. Such conserved DNA...
Gene Evolution - Fast or Slow?
In contrast, regions which code...

