DNA
sequence manipulations were performed using the SeqApp program,
version 1.9a169 [22], and phylogenetic analyses were implemented
through PHYLIP 5.57 [23]. Distance matrix analyses were according
to the method of Jukes and Cantor [24] with a masking function to
exclude ambiguous data, and phylogenetic tree construction was by
neighbour joining [25]. Phylogenetic analysis was performed for 287
positions which could be unambiguously aligned for all sequences used
in the analysis. Bootstrapping was conducted with 100 replicates using
the program SeqBoot [23]. Bootstrap supports for the sequence clusters
were similar to those found previously [17]. Recovered sequences were
also tested for homology to known sequences in the EMBL databank
using the FastA program [26]. Bands whose nucleotide sequences were
determined have been given labels in Figures 2 and 3 which correspond
to the sequence names beginning with a `B’ in Figure 1. The addition of
an asterisk to a band label (Figures 2 and 3) indicates a difference of one
base pair from the given numbered sequence. These differences have
been shown to be introduced at the ambiguous position of the reverse
primer by PCR [18] and have not been included in the phylogenetic
analysis.