Polymorphism of the nucleolus organizer region (NOR) on the putative sex chromosomes of Arctic char (Salvelinus alpinus) is not sex related

Kent M. Reed, Ruth B. Phillips

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

Polymorphism of the nucleolus organizer region (NOR) on the putative sex chromosomes of Arctic char (Salvelinus alpinus) was examined using conventional cytogenetic and molecular techniques. Variation was observed in the number, size and position of rDNA loci on the sex pair. Fluorescence in situ hybridization (FISH) analyses showed that the sex chromosomes of Arctic char lack the repetitive DNA sequences (MboI/Bg/II family) that are a prominent feature of the sex chromosomes of lake trout (S. namaycush). Southern analyses of genomic DNAs using an rDNA fragment as probe revealed extensive restriction fragment length polymorphism (RFLP) variation among individuals. Despite the presence of variation in all aspects of this rDNA locus, no sex-specific differences were detected. Repetitive DNAs (multicopy rDNA as in Arctic char or tandem repetitive DNA as in lake trout) appear to play important but different roles in the evolution of the sex chromosomes in these species.

Original languageEnglish (US)
Pages (from-to)221-227
Number of pages7
JournalChromosome Research
Volume5
Issue number4
DOIs
StatePublished - Sep 4 1997

Keywords

  • Arctic char
  • Fluorescence in situ hybridization
  • Heterochromatin
  • Lake trout
  • Nucleolus organizer region
  • Sex chromosomes

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