Figure 2

Phylogenetic tree of TipE gene family members in 11 insect species and Daphnia pulex. The phylogeny of TipE gene family members highlights the five groups of orthologues from the crustacean water flea, Daphnia pulex (Dpule) and 11 representative insect species: two fruit flies, Drosophila melanogaster (Dmela) and Drosophila mojavensis (Dmoja); three mosquitoes, Anopheles gambiae (Agamb), Aedes aegypti (Aaegy), Culex quinquefasciatus (Cquin); the silk moth, Bombyx mori (Bmori); the flour beetle, Tribolium castaneum (Tcast), the honey bee, Apis mellifera (Amell); the parasitoid wasp, Nasonia vitripennis (Nvitr); the pea aphid, Acyrthosiphon pisum (Apisu); and the human body louse, Pediculus humanus (Phuma). The clade of Teh3-Teh4 proteins is distinct from TipE-Teh1-Teh2, linked by dashed lines based on the phylogenetic tree of TipE gene family members in D. pulex and six selected insect species (coloured), rooted using the distantly related vertebrate big-conductance calcium-activated potassium channel beta-4 auxiliary subunits (KCNMB4) (see Additional file 3, Figure S2). The phylogeny resolves the D. pulex TipE orthologue, and although Teh1 and Teh2 orthologues are not confidently resolved, they can be identified by comparing their conserved motif architectures with the insect Teh1 and Teh2 orthologues (see Additional file 3, Figure S3). A single Teh3/4-like gene is found in the D. pulex genome, which probably reflects the ancestral pancrustacean genome, where a retrotransposition event before the insect radiation generated the Teh3 retrogene. This gene duplication may have created a functional redundancy which allowed for the loss of Teh4 orthologues in mosquitoes and the silk moth. The maximum likelihood phylogeny was built from the confidently-aligned regions of the multiple sequence alignment of member proteins (see Methods). Bootstrap support values from 100 samples are given and nodes with less than 60% support are collapsed.