Potamogeton × torssanderi triple hybrid and parental ITS sequences. Three diagnostic electropherogram clippings of directly sequenced P. × torssanderi ITS are shown along with the corresponding alignments of its parental taxa; relative positions are given above the alignments. Electropherograms of (A) and (B) were sequenced with the forward primer, (C) with the reverse primer; the plus strand is indicated in all cases. (A) Asterisks mark substitutions between parents; arrowheads indicate a 1-bp deletion in P. perfoliatus relative to P. lucens/P. gramineus. In the alignment, P. perfoliatus is written without a gap despite the indel position to reflect the sequencing reaction of the hybrid sample with the forward primer. (B) The upper P. perfoliatus sequence is aligned from the 3'-end without gaps (ignoring a 2-bp indel) reflecting sequencing with the reverse primer; the second is aligned as in (A); the third one is corrected for indels. Two positions with evidence for P. gramineus ITS are indicated by asterisks. The ‘C’ contributed by P. gramineus type 897 is recognized as ‘Y’ (C or T) in P. × torssanderi in both reading directions; the other position shows character states of all three parental species in forward direction [electropherogram; B ( = C, G, or T) in alignment], and of P. lucens/others in reverse direction (K = G or T). (C) Sequences are aligned at their 3'-end to reflect sequencing with the reverse primer, only the second P. perfoliatus sequence is aligned without gaps from the 5'-direction (forward primer). Arrowheads indicate a 2-bp deletion in P. perfoliatus (upper sequence in alignment). At the position marked by the right asterisk, all three parental species have different diagnostic bases, recognizable in reverse direction (electropherogram; H = A, C or T); in forward direction, only ‘C’ for P. gramineus and ‘A’ for P. lucens/P. perfoliatus ( = M, see alignment) are evident. Equal height of peaks at the left asterisk position indicates added-up ‘T’-signals of P. gramineus type 897 and P. perfoliatus, exceptionally matching the height of the ‘C’-signal of the otherwise dominating P. lucens sequence.