MICROHETEROGENEITY OF P60 CAPSID PROTEIN AND THE ENCODING GENE AMONG CONTEMPORARY ISOLATES OF RABBIT HEMORRHAGIC-DISEASE VIRUS

The gene encoding the p60 capsid protein from a Spanish isolate of the rabbit hemorrhagic disease virus (RHDV) has been cloned and sequenced . Both cDNA and the derived protein sequences have been compared with those from several contemporary European RHDV isolates. Genetic hetero geneity among cocirculating viruses is nearly constant along the p60-e ncoding gene, around 0.034 substitutions per nucleotide, and it does n ot allow prediction of the preferential regions for long-term fixation of mutations. However, sequence comparisons with the more distant, bu t phylogenetically closely related calicivirus, the European brown har e syndrome virus (EBHSV), reveal a great extent of genetic variability within both a segment of p60 gene (nucleotides 900-1300) and the enco ded polypeptide, suggesting the existence of strong selective pressure s acting over this region of the capsid protein.