Evolutionary Insights of the ZW Sex Chromosomesin Snakes: A New Chapter Added by the AmazonianPuffing Snakes of the Genus Spilotes.

Viana Viana,De Bello Cioffi De Bello Cioffi,Ezaz Ezaz,Feldberg Feldberg,Jackson Almeida Jackson Almeida

doi:10.3390/genes10040288

Viana Viana, De Bello Cioffi De Bello Cioffi + Show 3 more

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https://doi.org/10.3390/genes10040288

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Abstract

Amazonian puffing snakes (Spilotes; Colubridae) are snakes widely distributed in the Neotropical region. However, chromosomal data are scarce in this group and, when available, are only limited to karyotype description using conventional staining. In this paper, we focused on the process of karyotype evolution and trends for sex chromosomes in two Amazonian Puffer Snakes (S. pulllatus and S. sulphureus). We performed an extensive karyotype characterization using conventional and molecular cytogenetic approaches. The karyotype of S. sulphureus (presented here for the first time) exhibits a 2n = 36, similar to that previously described in S. pullatus. Both species have highly differentiated ZZ/ZW sex chromosomes, where the W chromosome is highly heterochromatic in S. pullatus but euchromatic in S. sulphureus. Both W chromosomes are homologous between these species as revealed by cross-species comparative genomic hybridization, even with heterogeneous distributions of several repetitive sequences across their genomes, including on the Z and on the W chromosomes. Our study provides evidence that W chromosomes in these two species have shared ancestry.

Highlights

The Colubridae family represents one of the most widely distributed groups of Caenophidian snakes, with more than 1800 species currently recognized [1]
Many species are found in the Neotropical region, which is well known for its high biodiversity and complex evolutionary history [7,8,9,10]
We focused on the process of karyotype evolution and trends of sex chromosome differentiation in the clade that harbors the most recently evolved species among Caenophidian snakes

Summary

Introduction

The Colubridae family represents one of the most widely distributed groups of Caenophidian snakes, with more than 1800 species currently recognized [1]. It is considered to be a monophyletic group supported by both morphological and molecular analyzes [2,3,4,5,6]. Many species are found in the Neotropical region, which is well known for its high biodiversity and complex evolutionary history [7,8,9,10]. The Amazon puffing snakes (Spilotes spp.) are among the largest species of the New. World Colubrids [11,12,13], occurring in different morpho-climatic landscapes in South America [14,15,16]. Spilotes sulphureus was described within the Pseustes genus [17]. Jadin et al [18]

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