Representation of Transcripts Coding for GRPs Representation of the Most Abundant Transcripts Coding for Specific Types of GRPs N° of ESTs N° of ESTs Observed Expected Observed N° clusters N° clusters Observed Expected Observed 59.620 45.333 34.421 27.312 25.617 14.130 Expected 17.678 17.217 3,301 9.432 22,749 17,247 12,185 Library SGFRs SGFAc SGFAc Library SGFRs SGFAc SGFAc SGFRs SGFAc SGFAc SGFAc SGFRs SGFAc SGFAc 57 57 47 33 33 16 21 21 6 13 23 23 17 47 23 23 16 11 11 10 10 17 1 1 8 8 Maruyama et al. BMC Genomics 2010, 11:363 http://www.biomedcentral.com/1471-2164/11/363 Table 3: Differential Abundance of Transcripts and Diversity of Types of GRPs in Salivary Gland Libraries from females of Rhipicephalus (Boophilus) microplus SGFRm), Rhipicephalus sanguineus (SGFRs)and Amblyomma cajennense (SGFAc) Representation of Transcripts Coding for GRPs Expected 45.380 35.667 35.579 Expected 22.688 19.383 12.870 Expected 13.322 13.783 3,699 4.568 17,251 13,753 12,815 Page 7 of 17 P value* P = 0.821 P = 0.006 P = 0.003 P value* P = 0.072 P = 0.015 P = 0.592 P value P = 0.372 P = 0.232 P = 0.424 P = 0.002 P = 0.936 P = 0.056 P = 0.396 Library SGFRm SGFRm SGFRs Library SGFRm SGFRm SGFRs Best match to NR protein database gi|45479213|unknow n Rhipicephalus haemaphysaloides Acanthoscurrin 64P Silk-like proteins from true spiders Library SGFRm SGFRm SGFRs SGFRs SGFRm SGFRm SGFRs N° of ESTs Library N° of ESTs Observed Observed *Chi-square test for representation of the glycine-rich proteins distributed in the three cDNA libraries. of the terms and SGFAc with 26.1% versus 12.1% of terms for SGFRs). Glycine-rich proteins related to epidermal development have also been found in others arthropods, such as the silkworm Bombix mori [14]. Interestingly terms related to development of epidermis were the most abundant category of all, assigned to SGFRs (70.2%), a library made from a heteroxenous, Brevirostrata tick. Over half (52.2%) of the terms assigned for SGFAc fell into the category "unknown", reflecting the fact that little information is available about biological characteristics of saliva from A. cajennense ticks. Phylogenetic analyses of Glycine-rich proteins Silk-like proteins Phylogenetic analysis of GRP contigs from the three ticks studied herein shows 3 distinct clades (numbered 1-3) as displayed in Figure 2. Two of them contain a group of contigs that presented similarities with silk proteins of spiders. One was similar to a flagelliform silk protein, (FSP; clade 1), which is a viscous, glue-like silk from orb- weaving spiders of the Nephila genus; another was similar to major ampullate spidroin (Masp; clade 2) from Kukul- cania hibernalis, a cribellate (i.e., it does not produce