Further insights into chromosomal evolution of the genus Enyalius with karyotype description of Enyalius boulengeri Etheridge, 1969 (Squamata, Leiosauridae)

Cynthia Aparecida Valiati Barreto,Marco Antônio Peixoto,Natália Martins Travenzoli,Késsia Leite De Souza,Renato Neves Feio,Jorge Abdala Dergam

doi:10.36253/caryologia-1120

Cynthia Aparecida Valiati Barreto, Marco Antônio Peixoto + Show 4 more

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https://doi.org/10.36253/caryologia-1120

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Journal: Caryologia	Publication Date: Dec 21, 2021
License type: CC BY 4.0

Affiliation: Universidade Federal de Viçosa

Abstract

The genus Enyalius is composed of 11 described species inhabiting forest areas in Amazônia, Cerrado and Atlantic forest biomes. Currently, eight species with high levels of chromosome variation have been karyotyped. The study aims to characterize the karyotype of Enyalius boulengeri, with classical and molecular techniques, and improve knowledge about the karyotype evolution of the lizard genus Enyalius. The species has 2n = 36 chromosomes (8m + 4sm + 24mc), FN = 24; NORs and 18S rDNA were subtelomeric and located on chromosome pair 2. Repetitive DNA probes (CAT)10 accumulated on centromeric and terminal regions of some macrochromosomes. (GA)15 probe showed conspicuous accumulation on the pericentromeric region of chromosome pairs 1 and 6. Repetitive FISH patterns obtained with (GC)15 probe marked the pericentromeric region of the first chromosome pair. All probes showed accumulation in the microchromosomes. The chromosomal formula found in E. boulengeri has been considered the ancestral karyotype for pleurodont Iguania. The genus Enyalius is characterized by two distinctive chromosomal groups; one with highly conserved karyotypes, whereas the other is karyotypically diverse. Our molecular cytogenetics data are promising and will increase knowledge about the genus Enyalius chromosome evolution.

Highlights

Cytogenetic studies on lizards of pleurodont Iguania infraorder suggest that there are two distinct trends on chromosome evolution in this taxon: some genera present chromosome variability, such as supernumerary chromosomes, sexual elements and large differences in chromosomal number and size
A secondary constriction was Enyalius boulengeri showed a 2n = 36 (12M + 24mc) karyotype that is ubiquitous among species of the genus and pleurodont Iguania (Gorman et al 1967; Pellegrino et al 1999; Bertolotto et al 2002; Bertolotto 2006; Rodrigues et al 2006; Rodrigues et al 2013)
It was observed a similarity between the nucleolar organizing region (NOR) and the 18S rDNA labeling at the distal end of the long arm of both homologues on chromosome pair 2

Summary

INTRODUCTION

Cytogenetic studies on lizards of pleurodont Iguania infraorder suggest that there are two distinct trends on chromosome evolution in this taxon: some genera present chromosome variability, such as supernumerary chromosomes, sexual elements and large differences in chromosomal number and size On the other hand, related species present variation in chromosome number and size and supernumerary elements (clade B sensu Rodrigues et al 2014). Two characters are highly conserved in Enyalus: the nucleolar organizing region is located on the chromosome pair number 2 and heterochromatic regions occur in the centromeric position, on M and on almost all mc (Bertolotto et al 2002). Phylogenetic relationships within this family are still unresolved, and studies employing banding techniques associated to molecular cytogenetics should reveal undetected synapomorphies. The study aims to characterize the karyotype of Enyalius boulengeri, with classical and molecular techniques and improve knowledge about the karyotype evolution of this genus

MATERIAL AND METHODS

DISCUSSION

CONCLUSION