DNA sequence variation in the ribosomal internal transcribed spacer region of freshwater Cladophora species (Chlotophytal)

Jane C Marks, M. P. Cummings

Research output: Contribution to journalArticle

31 Scopus citations


Freshwater species of Cladophora (Chlorophyta) are globally distributed and occupy an unusually wide range of ecological habitats. Delineating species is difficult because most easily observed morphological traits are highly variable and because sexual reproduction has not been clearly documented. Synthesizing ecological data on freshwater Cladophora species is problematic because it is unclear whether freshwater Cladophora species comprise many genetically distinct species or a few ecologically and morphologically variable and/or plastic species. We determined nucleotide sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal cistron freshwater Cladophora species from a wide range of habitats and geographic locations. We compared these sequences to those derived from culture collections of C. fracta and C. glomerata, the two most commonly reported freshwater Cladophora species. Cladophora fracta and C. glomerata had very similar ITS sequences (95.3%). all other sequences were identical to those from the C. fracta or C. glomerata culture collections with the exception of one California sample that was similar to both C. fracta (95.6%) and C. glomerata (92.4%). OTS genotypes did not correlate with morphology or geography. This analysis shows that common freshwater Cladophora species comprise very few (possibly one) ecologically and morphologically variable species.

Original languageEnglish (US)
Pages (from-to)1035-1042
Number of pages8
JournalJournal of Phycology
Issue number6
StatePublished - 1996
Externally publishedYes



  • Chlorophyta
  • Cladophora
  • freshwater algae
  • genetic diversity
  • internal transcribed spacer

ASJC Scopus subject areas

  • Aquatic Science
  • Plant Science

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