Metamorphosis in Xenopus laevis is not associated with large-scale nuclear DNA content variation

Jennifer L. Freeman, A. Lane Rayburn

Research output: Contribution to journalArticlepeer-review


Amphibian metamorphosis is a complex process that has been speculated to involve DNA amplification and chromatin rearrangement. While recent studies have concentrated on chromatin rearrangement, only a few studies have dealt with variation in the amount of DNA during amphibian metamorphosis. In this study, nuclei were isolated from Xenopus laevis at various developmental stages. The nuclei were examined in both an unfixed state and a fixed state. The nuclei were stained with propidium iodide and analyzed by flow cytometry to determine their fluorescence intensity. The unfixed nuclei had higher fluorescence variation compared with the fixed nuclei. This increase in variation appeared due to the presence of nuclei of variable fluorescence intensity within the unfixed nuclei. Upon optimum fixation, which has been speculated to result in more homogeneous chromatin conformation and to reduce staining artifacts, the nuclei were observed to have less fluorescence intensity variation. The differential fluorescence observed in this study is consistent with the hypothesis that large-scale intra-individual DNA variation is not associated with amphibian metamorphosis.

Original languageEnglish (US)
Pages (from-to)4473-4477
Number of pages5
JournalJournal of Experimental Biology
Issue number25
StatePublished - Dec 2004


  • Development
  • Flow cytometry
  • Metamorphosis
  • Nuclei
  • Xenopus

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Insect Science


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