Cytogenetics of the land snails Cantareus aspersus and C. mazzullii (Mollusca: Gastropoda: Pulmonata).
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.
Vitturi
Roberto
R
Dipartimento di Biologia Animale, Università di Palermo, Via Archirafi 18, 90123 Palermo, Italy.
Libertini
Angelo
A
Sineo
Luca
L
Sparacio
Ignazio
I
Lannino
Antonella
A
Gregorini
Armando
A
Colomba
Mariastella
M
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
D004275:DNA, Ribosomal; D004247:DNA