Maruyama et al. BMC Genomics 2010, 11:363 http://www.biomedcentral.com/1471-2164/11/363 Page 9 of 17 Figure 2 Dendogram of Glycine-rich proteins of A. cajennense, R. sanguineus and R. microplus ticks. The protein sequences were aligned by the Clustal X program (Thompson et al., 1997), and the dendrogram was calculated using the Mega package (Kumar et al., 2004) after 10,000 bootstraps with the neighbor joining (NJ) algorithm. The bar at the bottom represents 20% amino acid substitution. The Roman numerals in the figure indicate the three most distinct clades. Filled symbols are transcripts that presented matches with spider silk proteins and empty symbols are transcripts that displayed matches with cement-like proteins of ticks in Arachnida database (from NCBI). Circle: R. microplus; square: R. sanguineus; triangle: A. cajenn- ense. All similarities (best match against Arachnida database) of transcripts in dendrogram can be observed in Table 2. contigs from the work of Francischetti et al. (2009; http:// exon.niaid.nih.gov/transcriptome/tick_review/Sup- Table-1.xls.gz) [18] that reviewed all of the available sali- vary components of ticks. This work described a super- family of glycine-rich proteins for argasid and ixodid ticks (mainly Brevirostrata ticks). We observed in this work that Argasid ticks produce only three types out of over four hundred types of GRPs. This maybe due to the fact that Argasid ticks are rapid feeders and complete a blood meal in minutes. We also observed that the majority of the GRPs found in Prostriate ticks (genus Ixodes), are col- lagen-like proteins. This group appears to have a primi-