Chromosome Mapping of 5S Ribosomal Genes in Indo-Pacific and Atlantic Muraenidae: Comparative Analysis by Dual Colour Fluorescence In Situ Hybridisation.

Elisabetta Coluccia,Susanna Salvadori,Federica Deidda,Cinzia Lobina,Cristina Porcu,Riccardo Melis,Blondine Agus

doi:10.3390/genes11111319

Elisabetta Coluccia, Susanna Salvadori + Show 5 more

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https://doi.org/10.3390/genes11111319

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Journal: Genes	Publication Date: Nov 6, 2020
Citations: 3	License type: CC BY 4.0

Affiliation: University of Cagliari

Abstract

The Muraenidae is one of the largest and most complex anguilliform families. Despite their abundance and important ecological roles, morays are little studied, especially cytogenetically, and both their phylogenetic relationships and the taxonomy of their genera are controversial. With the aim of extending the karyology of this fish group, the chromosomal mapping of the 5S ribosomal gene family was performed on seven species belonging to the genera Muraena and Gymnothorax from both the Atlantic and Pacific oceans. Fluorescence in situ hybridisation (FISH) experiments were realized using species-specific 5S rDNA probes; in addition, two-colour FISH was performed to investigate the possible association with the 45S ribosomal gene family. Multiple 5S rDNA clusters, located either in species-specific or in possibly homoeologous chromosomes, were found. Either a syntenic or different chromosomal location of the two ribosomal genes was detected. Our results revealed variability in the number and location of 5S rDNA clusters and confirmed a substantial conservation of the number and location of the 45S rDNA.

Highlights

Within the teleosts, the Elopomorpha—tarpons, eels, and relatives—is considered to be one of the major extant taxa, besides the Osteoglossomorpha and Clupeocephala
Our results revealed a variability in the number and location of 5S rDNA clusters, in some cases syntenic with 45S rDNA or associated with heterochromatic regions, and confirmed a greater conservation of the number and location of the 45S rDNA clusters among species
In the 7 Muraenidae species studied, a total of 19 5S rDNA sites were found, 1 to 4 5S rDNA sites per species were present, 90% of which were in internal positions, in accordance with the most frequent situation found in vertebrates, and considered beneficial for the protection of these sequences from rearrangements [45] (Table 1)

Summary

Introduction

The Elopomorpha—tarpons, eels, and relatives—is considered to be one of the major extant taxa, besides the Osteoglossomorpha and Clupeocephala. The Elopomorpha is the sister group to the rest of the teleosts [1]. This group includes about 1000 species, with Anguilliformes being the most diverse order, containing over 90% of the species [2]. Of the group is currently accepted based on both molecular and morphological evidence; their most remarkable synapomorphy is the leptocephalus larva [1,3]. Within the Anguilliformes order, four monophyletic groups, the Protanguilloidei, Muraenoidei, Anguilloidei, and Congroidei, have been recognized [1]

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