PMC5358934_01
(a) Phylogenetic analysis of full genome HDV sequence of husband ( ) and wife ( ) with GenBank reference sequences for all HDV genotypes. The date of specimen collection is provided (Y-M-D). (b) Phylogenetic analysis of the delta antigen coding region (357 bp, approximately nt 906-1262 based on the numbering of GenBank accession no. M58629) from longitudinal specimens of husband ( ) and wife ( ). The date of specimen collection is provided beside each sequence (Y/M/D). Sequenced diagnostic reference samples unrelated to the couple, but residing in the same Canadian location are shown ( ). Maximum likelihood phylogenetic analysis was performed using MEGA7 with 500 bootstrap replicates and the Tamura-3-parameter + Gamma substitution model as the most appropriate model for the alignment data. Bootstrap confidence values >=60% are shown. The ruler shows the branch length for a pairwise distance equal to (a) 0.1 or (b) 0.05. The GenBank accession numbers for the sequences reported are KY379238 to KY379247, KY458181, KY458182.
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Both sequences were HDV genotype 1 (Fig. 1a). Phylogenetic analysis of longitudinal HDV delta antigen (DAg) coding sequence (357 bp, GenBank accession numbers KY379238 to KY379245, KY458181, KY458182; Fig. 1b) from the couple demonstrate HDV evolution following transmission, with 2 nucleotide substitutions apparent in the husband's DAg sequence (at nt 1000 and nt 1246) differing from the DAg sequence of the wife close to the 6-month time of suspected transmission (Fig. 2).
Longitudinal HDV delta antigen region sequence (357 bp) from spousal couple specimens, by date (Y-M-D). The major nucleotide substitutions observed between husband and wife or among longitudinal samples are denoted by the boxes. *Nucleotide numbering is based on GenBank accession no. M58629 (357 bp region is found at nt 906 to nt 1262).
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The husband's DAg sequence remained nearly identical throughout the 16-month follow-up (over 357 bp; Fig. 2), while the wife's DAg sequence displayed increased heterogeneity, particularly following initiation of treatment (16-07-06 sequence; Figs. 1 b and 2).