engleski

Satellite DNAs of the species Pimelia criba and Pimelia elevata (Insecta, Coleoptera)

Satellite DNAs often show high variability in sequence, reiteration frequency and chromosomal distribution even among closely related species. Here are presented the results of a molecular and cytogenetic survey of satellite DNAs of two congeneric tenebrionid species, endemic to the Balearic islands: Pimelia criba and P. elevata. Genomes of both species comprise a significant amounts of one major satellite DNA (40%)AT rich with monomer unit 357 bp long. P.criba and P. elevata consensus satellite sequences share very high mutual homology of 99.2% and they are also highly homologous to the satellite of four continental Pimelia species. The computer modeling of sequence induced curvature of DNA helix axis predicted a tertiary structure of the left superhelix. Pulsed field gel electrophoresis of genomic DNA digested with nonsatellite cutting restriction endonucleases, and subsequent hybridization with satellite probe, revealed the lengths of satellite DNA clusters ranging from several kb to more than 1.5 Mb. C-banding revealed the presence of large pericentric heterochromatic blocks on all chromosomes, while fluorescent in situ hybridization localized satellite sequences within those heterochromatic regions.

satellite DNA; genome organization

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