Skinks (Reptilia: Scincidae) Have Highly Conserved Karyotypes as Revealed by Chromosome Painting

Abstract

Skinks represent the most diversified squamate reptiles with a great variation in body size and form, and are found worldwide in a variety of habitats. Their remarkable diversification has been accompanied by only a few chromosome rearrangements, resulting in highly-conservative chromosomal complements of these lizards. In this study cross-species chromosome painting using Scincus scincus (2n = 32) as the source genome, was used to detect the chromosomal rearrangements and homologies between the following skinks: Chalcides chalcides (2n = 28), C. ocellatus (2n = 28), Eumeces schneideri (2n = 32), Lepidothyris fernandi (2n = 30), Mabuya quinquetaeniata (2n = 32). The results of this study confirmed a high degree of chromosome conservation between these species. The main rearrangements in the studied skinks involve chromosomes 3, 5, 6 and 7 of S. scincus. These subtelocentric chromosomes are homologous to the p and q arms of metacentric pair 3 and 4 in C. chalcides, C. ocellatus, L. fernandi, and M. quinquetaeniata, while they are entirely conserved in E. schneideri. Other rearrangements involve S. scincus 11 in L. fernandi and M. quinquetaeniata, supporting the monophyly of Lygosominae, and one of the chromosomes S. scincus 12–16, in M. quinquetaeniata. In conclusion, our data support the monophyly of Scincidae and confirm that Scincus-Eumeces plus Chalcides do not form a monophyletic clade, suggesting that the Scincus-Eumeces clade is basal to other members of this family. This study represents the first time the whole genome of any reptile species has been used for cross-species chromosome painting to assess chromosomal evolution in this group of vertebrates.

A Short Introduction to Cytogenetic Studies in Mammals with Reference to the Present Volume

“…Cross-species painting between these species has been very informative, although the hybridization efficiency has been less than in birds or mammals: this is understandable in view of the longer divergence times. The results are consistent with greater genome conservation and even fewer evolutionary rearrangements than in birds [Giovannotti et al, 2009;.…”

Molecular phylogeny of the genus Eumeces Wiegmann, 1834 (Reptilia: Scincidae) in Iran, inferred from 16s mitochondrial DNA

“…Most studies based on karyological analyses (Kupriyanova, 1986;Caputo et al, 1993Caputo et al, , 1994 and morphological/molecular studies (Carranze et al 2008) showed the paraphyly of E.schneiderii group species and argued that Scincus may be derived from an E. schneiderii-like stock. The Scincus Eumeces clade considered basal to other members of the family (Giovannotti et al, 2009).…”

Chromosome Banding in Amphibia. XXXI. The Neotropical Anuran Families Centrolenidae and Allophrynidae

“…Such experiments have been successfully performed for comparative cytogenetic studies in mammals, birds, reptiles, and fishes [e.g. Reed et al, 1995;Yang et al, 1995Yang et al, , 1999Yang et al, , 2003Griffin et al, 1999;Campos-Ramos et al, 2001;Phillips et al, 2001;Rens et al, 2001Rens et al, , 2003Rens et al, , 2004Rens et al, , 2006Harvey et al, 2002;Liu et al, 2002;Guttenbach et al, 2003;Grützner et al, 2004;Nanda et al, 2006Nanda et al, , 2007Nanda et al, , 2008Ferguson-Smith and Trifonov, 2007;Henning et al, 2008;Giovanotti et al, 2009;Cioffi et al, 2013]. Previous cytogenetic studies on NORs in Anura clearly demonstrate that the overwhelming majority of species possess only a single 'standard' pair of NORs [Schmid, 1980;King, 1990;Green and Sessions, 2007;Schmid et al, 2010Schmid et al, , 2012.…”