FIG. 3.
Mutant alleles and homology modeling of the 21 b insertion. (A) The mutant alleles (M1: 3 nt insertion; M2: 2 nt substitution; M3: 4 nt deletion) identified at exon 3 were compared to the wild-type sequence. 2nd and ♂ indicates the instar/life stage the mutation was identified in (2 adult males shared this mutation). (B) The 21 bp insertion (M) at exon 5 in a first nymphal instar. (C) Predicted 3D structure of the wild-type B. tabaci white protein (left) compared to the structure of the in-frame 21 bp insertion mutant (right). The insertion is predicted to cause a loop (arrow) across the channel pore, sterically hindering function of the transporter, leading to a null mutation.