Replication slippage in the evolution of potyviruses

1 Research School of Biological Sciences, Institute of Advanced Studies, Australian National University, Canberra and 2 Centre for Molecular Biotechnology, Queensland University of Technology, Brisbane, Australia Recently published evidence for sequence repetition in potyvirus genomes prompted us to analyse the published complete genome sequences and coat protein gene sequences of viruses of this family for evidence of replication slippage. Five of nine complete genomic sequences and 17 of 32 coat protein genes had significant sequence repetitions. Most of these were in coat protein genes, although the 5' region of the turnip mosaic virus genome also showed evidence of slippage. The results suggest that replication slippage may be involved in the evolution of viruses, as well as prokaryotes and eukaryotes, and that slippage can occur in both RNA and DNA when it is being replicated. * Author for correspondence. Fax +61 6 249 4437. e-mail gibbs@rsbs-central.anu.edu.au Present address: MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK. Received 21 April 1995; accepted 23 August 1995.