Characterisation of a novel recombination event in the norovirus polymerase gene.

This communication describes a novel recombination event in the norovirus genome. Similarity plot analysis of a nucleotide fragment (1003 bp) amplified from a norovirus positive clinical specimen (IrlN05771) identified a previously undescribed recombination point in the 3' region of the polymerase gene (nucleotide position 4889 bp). Nucleotide multiple alignments demonstrated that Irl05N771 shared 78.6% and 94% identity with all other Irish norovirus sequences before and after the recombination point, respectively and confirmed the sequence as a genogroup II/type 4 recombinant. Irl05N771 shared more identity with Asian norovirus sequences. This is the first description of recombination within the norovirus polymerase and highlights the continuous genetic evolution of noroviruses.