Alignment of a random subset of haplotype sequences highlighting distinct sequence patterns of ABO groups. For each ABO group, 6 haplotype sequences were randomly picked. For the subgroup ABO∗O.01.01, we show 6 sequences for both subgroups (g1 and g2) observed in the phylogenetic tree (Figure 3) and haplotype network (Figure 4). Black bars on the haplotype sequences highlight positions that are different to the ABO reference sequence (NG_006669.2). The identity graph (Identity) above the sequences indicates the mean pairwise identity over all sequence pairs by gene position; green represents 100% identity, orange identity between 30% and 99%, and red identity <30%. The ABO gene structure is provided at the top of the graph for orientation purpose.