Maruyama et al. BMC Genomics 2010, 11:363 http://www.biomedcentral.com/1471-2164/11/363 Page 12 of 17 Figure 4 Dendogram of glycine-rich proteins that present similarities with spider silk proteins. Transcripts of proteins described in this work ( : R. microplus; : R. sanquineus; ▲: A. cajennense) and transcripts of proteins obtained in the catalogue of annotated salivary proteins available in Francischetti et al. (2009) were used to construct phylogenies (Amb var: A. variegatum; Amby am: A. americanum; Der and: D. andersoni; Rh ap: R. appendiculatus; Rh micro: R. microplus; the numbers refer to contig in Sup-Table1 [18]). GRPs present biochemical characteristics that could possibly be involved in stabilizing the tick to its feeding site for long periods due to their putative structural and mechanical functions inferred from the abundance of the amino acid glycine. GRPs may also block host immune system molecules that enter in contact with the tick mouthparts [4]. Many contigs were similar to silk pro- teins from spiders, such as fibroin, dragline, flagelliform,