title: Cytogenetics of the land snails Cantareus aspersus and C. mazzullii (Mollusca: Gastropoda: Pulmonata).
abstract: A cytogenetic study was carried out on the chromosomes and nuclear DNA contents of the land snails Cantareus aspersus and C. mazzullii (Gastropoda: Pulmonata). Chromosomes were studied using Giemsa staining, banding methods and fluorescent in situ hybridization (FISH) with three repetitive DNA probes [18S rDNA, (GATA)(n) and (TTAGGG)(n)]. Results were very similar in the two species both showing (1) 54 bi-armed chromosomes [submetacentrics (SM) + metacentrics (M) + subtelocentrics (ST)]; (2) 10 terminal NORs after sequential application of rDNA FISH and silver staining; (3) uniform DNA fluorescence with CMA(3) and DAPI staining and (4) genomic composition considerably enriched both in highly- and moderately-repeated DNAs. The telomeric (TTAGGG)(n) sequence hybridized with the termini of all of the chromosomes in the two species. In spite of their apparent karyological uniformity, flow cytometry DNA assays showed that C. aspersus and C. mazzullii are characterized by different nuclear DNA content (C values are 3.58 and 3.08 pg, respectively) and slightly different base composition in their genomes. Present data on GS and AT% in C. mazzullii and C. aspersus confirm the trend toward high GS values and GC percentages among land snails.
authors.affiliation: Dipartimento di Biologia Animale, Università di Palermo, Via Archirafi 18, 90123 Palermo, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Vitturi
authors.forename: Angelo
authors.initials: A
authors.lastname: Libertini
authors.forename: Luca
authors.initials: L
authors.lastname: Sineo
authors.forename: Ignazio
authors.initials: I
authors.lastname: Sparacio
authors.forename: Antonella
authors.initials: A
authors.lastname: Lannino
authors.forename: Armando
authors.initials: A
authors.lastname: Gregorini
authors.forename: Mariastella
authors.initials: M
authors.lastname: Colomba
mesh_terms: D000818:Animals; D001483:Base Sequence; D002871:Chromosome Banding; D003582:Cytogenetics; D004247:DNA / Q000032:analysis; D004275:DNA, Ribosomal / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D012091:Repetitive Sequences, Nucleic Acid; D012908:Snails / Q000235:genetics*; D013045:Species Specificity; D013194:Staining and Labeling; D016615:Telomere / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal; D004247:DNA