Open Access

scDNA-DNA hybridization studies in Pacific and Caribbean isolates ofDictyosphaeria cavernosa (Chlorophyta) indicate a long divergence

  • J. L. Olsen1, 2,
  • W. T. Stam1,
  • P. V. M. Bot1 and
  • C. van den Hoek1
Helgoländer Meeresuntersuchungen41:BF02366200


Genomic size and complexity were calculated for the pantropical chlorophyte,Dictyosphaeria cavernosa (Cladophorales). Genome characterization of the Hawaiian material by means of DNA renaturation studies showed highly repetitive (31.3%), middle repetitive (42.7%), and single-copy (25.8%) fractions; and an estimated haploid genome size of 1.79 pg DNA. A G:C content of 43% was calculated from a melting curve of DNA. Pacific and Caribbean isolates of this species were compared using single-copy nuclear DNA-DNA hybridization. Results show a relatively low thermal stability of the hybridized DNA (Δ Tm(e)=10°C) which suggests that these Pacific and Caribbean lineages may have been separated for up to 55 Ma.