Chromosomal stasis in distinct families of marine Percomorpharia from South Atlantic.

Fabilene Gomes Paim,Paulo Roberto Antunes De Mello Affonso,Débora Diniz,Leandro Aragão Da Hora Almeida,Claudio Oliveira,Patrícia Elda Sobrinho-Scudeler

doi:10.3897/compcytogen.11(2).11942

Fabilene Gomes Paim, Paulo Roberto Antunes De Mello Affonso + Show 4 more

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https://doi.org/10.3897/compcytogen.11(2).11942

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Journal: Comparative cytogenetics	Publication Date: May 4, 2017
Citations: 10	License type: CC BY 4.0

Abstract

The weakness of physical barriers in the marine environment and the dispersal potential of fish populations have been invoked as explanations of the apparent karyotype stasis of marine Percomorpha, but several taxa remain poorly studied cytogenetically. To increase the chromosomal data in this fish group, we analyzed cytogenetically three widespread Atlantic species from distinct families: Chaetodipterus faber Broussonet, 1782 (Ephippidae), Lutjanus synagris Linnaeus, 1758 (Lutjanidae) and Rypticus randalli Courtenay, 1967 (Serranidae). The three species shared a karyotype composed of 2n=48 acrocentric chromosomes, single nucleolus organizer regions (NORs) and reduced amounts of centromeric heterochromatin. A single NOR-bearing pair was identified in all species by physical mapping of 18S rDNA while non-syntenic 5S rRNA genes were located at centromeric region of a single pair. The similar karyotypic macrostructure observed in unrelated groups of Percomorpharia reinforces the conservative karyoevolution of marine teleosteans. Nonetheless, the species could be differentiated based on the pair bearing ribosomal cistrons, revealing the importance of microstructural analyses in species with symmetric and stable karyotypes.

Highlights

Perciformes have long been regarded as the largest order of vertebrates with nearly 10.000 species, 1540 genera, and 160 families, most of them inhabiting the marine environment (Nelson 2006, Helfman et al 2009)
To test the corollary that the high dispersal and gene flow associated with the weakness of geographic barriers accounts for the chromosomal stasis in marine Percomorpharia groups, we analyzed cytogenetically three widespread Atlantic species from distinct families: Chaetodipterus faber (Ephippidae), Lutjanus synagris (Lutjanidae) and Rypticus randalli (Serranidae). Besides inferring their karyoevolutionary pathways, we provided the first cytogenetic report in C. faber and R. randalli
The nucleolus organizer regions (NORs) in C. faber were located at interstitial position on long arms of pair 3 (Figure 1A, box)

Summary

Introduction

Perciformes have long been regarded as the largest order of vertebrates with nearly 10.000 species, 1540 genera, and 160 families, most of them inhabiting the marine environment (Nelson 2006, Helfman et al 2009). The presence of 24 acrocentric pairs is shared by several species from distinct families of Perciformes (Affonso et al 2001, Accioly and Molina 2007, 2008, Cipriano et al 2008, Motta Neto et al 2011a, 2011b, 2012, Molina et al 2012, Molina et al 2013, Costa et al 2016) This pattern raises some intriguing questions: (1) how could such a morphologically diversified group evolve without significant chromosomal changes (Brum 1996, Galetti et al 2000, Molina 2007)? This pattern raises some intriguing questions: (1) how could such a morphologically diversified group evolve without significant chromosomal changes (Brum 1996, Galetti et al 2000, Molina 2007)? (2) What are the advantages (if any) of maintaining stable karyotypes?

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Conclusion