Fig. 2.

Protobothrops flavoviridis x P. elegans hybrids express phospholipases A₂ from both parental venoms. a Aligned PLA₂ transcripts from P. flavoviridis and P. elegans transcriptomes. The solid heavy vertical line separates the signal peptides from the expressed PLA₂s. A noncatalytic, myotoxic PLA₂ transcript (comp43_c0_seq1) from P. elegans specimen #3 accounted for 73.4 % of all P. elegans transcripts (Additional file 2: Table S1). This protein was heavily expressed in all three specimens and in both hybrids (Fig 3). A homologous transcript was found in the transcriptome of P. flavoviridis specimen #3, but it constituted less than 0.05 % of all P. flavoviridis transcripts (Additional file 3: Table S2). No peptides from this myotoxic PLA₂ transcript were detected in venoms of any P. flavoviridis specimens, or of the hybrids (Fig 3). P. elegans transcript comp47_c0_seq1 is homologous to P. flavoviridis transcript comp41_c0_seq1 (Fig 3). P. elegans specimens expressed the PLA₂ corresponding to the former transcript, while P. flavoviridis specimens expressed the latter. Hybrids expressed both (Fig 3; Additional file 8: Figure S5). The P. flavoviridis transcriptome also contained two additional PLA₂ trancripts, comp40_c0_seq1 and comp48_c0_seq1 (Additional file 3: Table S2). These had no homologs in the P. elegans transcriptome, but hybrids produced both of these, as did all three P. flavoviridis specimens (Fig 3; Additional file 8: Figure S5). b Peptide coverage of venom PLA₂ transcripts is similar between hybrids and non-hybrid specimens. Peptides from P. elegans venoms are indicated by green bars above the sequences, while those from P. flavoviridis venoms are in blue and those of hybrids are in gray. For any given transcript, peptides were sequenced from essentially the same portions of the PLA₂ in both hybrid and non-hybrid venoms