title: The Anolis Lizard Genome: An Amniote Genome without Isochores?
abstract: Two articles published 5 years ago concluded that the genome of the lizard Anolis carolinensis is an amniote genome without isochores. This claim was apparently contradicting previous results on the general presence of an isochore organization in all vertebrate genomes tested (including Anolis). In this investigation, we demonstrate that the Anolis genome is indeed heterogeneous in base composition, since its macrochromosomes comprise isochores mainly from the L2 and H1 families (a moderately GC-poor and a moderately GC-rich family, respectively), and since the majority of the sequenced microchromosomes consists of H1 isochores. These families are associated with different features of genome structure, including gene density and compositional correlations (e.g., GC3 vs flanking sequence GC and intron GC), as in the case of mammalian and avian genomes. Moreover, the assembled Anolis chromosomes have an enormous number of gaps, which could be due to sequencing problems in GC-rich regions of the genome. In conclusion, the Anolis genome is no exception to the general rule of an isochore organization in the genomes of vertebrates (and other eukaryotes).
authors.affiliation: Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy maria.costantini@szn.it gbernardi@uniroma3.it.
authors.forename: Maria
authors.initials: M
authors.lastname: Costantini
authors.affiliation: Unidad de Biología Molecular, Instituto Pasteur de Montevideo, Montevideo, Uruguay.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Greif
authors.affiliation: Sección Biomatemática, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alvarez-Valin
authors.affiliation: Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy Science Department, Roma Tre University, Rome, Italy maria.costantini@szn.it gbernardi@uniroma3.it.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bernardi
mesh_terms: D000818:Animals; D001482:Base Composition; D002874:Chromosome Mapping; D019143:Evolution, Molecular; D040481:Genome Components; D032085:Isochores; D008116:Lizards / Q000235:genetics*
chemical_list: D032085:Isochores
keywords: genome structure and evolution; isochores; reptiles