Recent advances in the study of ciliate genes.

This review gives a brief report on some recent advances in the study of molecular biology of ciliate genes. The main emphasis will be put on those results which may contribute to a better understanding of how gene structure and genome organization has evolved in ciliates. New data will be discussed in relation to the contribution they might give for a general understanding of eukaryotic gene evolution. The whole topic is divided into four parts: (1) a short introduction into genome organization of ciliates and an account of new insights in this field; (2) new results about telomere formation and replication; (3) regulation of transcription with new details about the atypical usage of the genetic code; (4) some speculations on unresolved problems and their possible solution by new methods. Other important new aspects of the molecular biology of ciliates which would fit well into this context, for example RNA self-splicing and evolutionary divergence of 17 S rRNA sequences, are not included as excellent newer reviews are available [e.g., 13-15, 42].