Analysis of serine peptidase inhibitors (serpins). Phylogenetic tree based on maximum likelihood analysis Dermacentor variabilis midgut protein and published serpin sequences from various tick species including 17 serpins, known as lospin, from Amblyomma americanum. The transcript identified in this analysis is in bold (DvM). Phylogenetic analysis was conducted on protein alignments using Tree Puzzle version 5.2. Values at nodes represent calculated internal branch node support (1000 replications). D. variabilis (Dv), Ixodes scapularis (Is), Amblyomma americanum (Aa), Haemaphysalis longicornis (Hl), Rhipicephalus appendiculatus (Ra), I. ricinus (Ir), Drosophila melanogaster (Dm), R. (Boophilus) microplus (Bm), Brugia malayi (Bma).