Molecular and General Genetics MGG

, Volume 230, Issue 1, pp 155–160

Demonstration of nucleomorph-encoded eukaryotic small subunit ribosomal RNA in cryptomonads


  • Uwe -G. Maier
    • Institut für Biologie II, ZellbiologieUniversität Freiburg
  • Claudia J. B. Hofmann
    • Institut für Biologie II, ZellbiologieUniversität Freiburg
  • Stefan Eschbach
    • Institut für Biologie II, ZellbiologieUniversität Freiburg
  • Jörn Wolters
    • Institut für Allgemeine Mikrobiologie
  • Gabor L. Igloi
    • Institut für Biologie III

DOI: 10.1007/BF00290663

Cite this article as:
Maier, U.-., Hofmann, C.J.B., Eschbach, S. et al. Molec. Gen. Genet. (1991) 230: 155. doi:10.1007/BF00290663


In cryptomonads, unicellular phototrophic flagellates, the plastid(s) is (are) located in a special narrow compartment which is bordered by two membranes; it harbours neither mitochondria nor Golgi dictyosomes but comprises eukaryotic ribosomes and starch grains together with a small organelle called the nucleomorph. The nucleomorph contains DNA and is surrounded by a double membrane with pores. It is thought to be the vestigial nucleus of a phototrophic eukaryotic endosymbiont. Cryptomonads are therefore supposed to represent an intermediate state in the evolution of complex plastids from endosymbionts. We have succeeded in isolating pure nucleomorph fractions, and can thus provide, using pulsed field gel electrophoresis, polymerase chain reaction and sequence analysis, definitive proof for the eukaryotic nature of the symbiont and its phylogenetic origin.

Key words

CryptomonadsNucleomorphSmall subunit ribosomal RNA

Copyright information

© Springer-Verlag 1991