Chromosomal polymorphism and molecular variability in the pearly razorfish Xyrichtys novacula (Labriformes, Labridae): taxonomic and biogeographic implications

Sex Chromosomes and Internal Telomeric Sequences in Dormitator latifrons (Richardson 1844) (Eleotridae: Eleotrinae): An Insight into Their Origin in the Genus

“…The mapping of telomeric (TTAGGG)n probes in vertebrate chromosomes showed that telomeric motifs could also be located interstitially along chromosome arms (interstitial telomeric sequences, ITSs), in pericentromeric/centromeric regions, or between the centromere and the telomere [ 65 , 66 ]. In fish chromosomes, these non-functional telomeres allow us to better elucidate chromosomal rearrangements in specific taxonomic groups [ 7 , 62 ] or to disentangle the evolutionary relationships of ancient species and wider taxonomic groups [ 67 ]. In the genome of D. latifrons , many ITSs were detected in pericentromeric regions, and some correspond to heterochromatic ITSs (het-ITSs), i.e., blocks of several hundreds of kilobases within or close to heterochromatic areas [ 68 ], that have been identified in different vertebrate species [ 65 ].…”

“…Assays for mapping onto chromosome 5S rDNA, 18S rDNA (ribosomal genes), and telomeric repeats were performed via fluorescence in situ hybridization (FISH) [ 46 ]. Probes for 5S rDNA, 18S rDNA, and telomeric repeats were obtained and labeled by PCR using primers and procedures previously reported [ 7 ]. Biotin-labeled probes were detected with fluorescein-conjugated avidin (FITC, Sigma-Aldrich, St. Louis, MO, USA) and digoxigenin-labeled probes were visualized using anti-digoxigenin-rhodamine conjugate (Roche Applied Science, Basel, Switzerland).…”

“…Research on fish systematics and evolution has expanded over time, including, in recent decades, molecular taxonomy, developmental biology, and new tools like 3D imaging [ 2 ]. Cytogenetic analyses join these new tools, providing new evidence of the existence of cryptic species and evolutionary divergence ([ 7 ] and references therein) and giving rise to a prosperous field focused on neotropical species [ 8 , 9 ].…”

Complete mitochondrial genome of the pearly razorfish Xyrichtys novacula: phylogenetic analysis of its placement within the Labridae family

“…The phylogeny of the Labridae has been previously reported (Westneat and Alfaro 2005), but the pearly razorfish was not considered. Furthermore, important genetic differences have been found among Atlantic and Mediterranean populations, suggesting different cryptic species across X. novacula (Nirchio et al 2019). The information we provide can be useful for future phylogenetic and taxonomic studies on the pearly razorfish and closely related taxa.…”

Fish Cytogenetics: Present and Future

“…In this picture, cytogenetics analysis is dismissed, although karyotype data both represent the pre-requisite for genome analysis and might provide support in demonstrating the existence of reproductive barriers. As an example, in the last decade, new marine and freshwaters sibling (or cryptic) species and parapatric divergent populations were disclosed thanks to cytogenetic analysis [ 3 , 4 , 5 , 6 ]. These cases represent exceptions, as the karyotypes (and the genomes) of fishes are poorly studied compared to other vertebrates, or at least not proportionally to the species richness of this group.…”