It was our last choice of the tested assemblers, according to evaluation metrics used. We also verified that some software works better with different clustering measures, such as the Celera assembler, which more effectively maps all the assembled reads into clusters. Most researchers would agree that the problem of sequence assembly and consensus production is highly complex and has not yet been solved, although most papers in the field simply choose a software program and proceed with assembly without further evaluations. Because sequence clustering is dependent on the informational content of the original reads, we recommend that authors test the appropriateness of the software for their own data before commencing the Lomitapide Mesylate annotation and analysis of unigenes. Based on the number of unigenes found here, we suspect that we have sequenced most of the coding sequences expressed by Actinopus spp. and G. cancriformis in their spinning glands. The number of unigenes in the Unigene database for the tick I. scapularis suggests that a number of unigenes in excess of the 25,663 found for G. cancriformis may be the rule for the Chelicerata clade. This excess of unigenes cannot be explained simply by the small size of the NGS-generated unigenes, although many unigenes probably represent either 39 or the 59 portions of genes. Our inability to identify most of the G. cancriformis unigenes by BLAST analysis indicates a lack of interest in Chelicerata clade genomics. We tried to fix this knowledge gap in the present publication by identifying more than 30,000 new genes for this clade and making them available to the research community in the SRA database. The amazing genetic Butenafine hydrochloride repertoire of spiders with their highly specialized tissues, such as the spinning and venom glands, will help researchers make biotechnological breakthroughs in the coming years, as has been recently discussed in the specialized literature. Remarkably, we found the metalloproteases from the astacin family to be extremely significant in the G. cancriformis spinning gland transcriptome. Genes from this family, which still have unknown functions, corresponded to 1.8% of all transcripts sequenced in the spinning glands, a number approximately 3.6 times larger than the number of expressed spidroin genes. Moreover, among the gene families that have undergone major amplifications since the ancestral split between the Mygalomorphae and Araneomorphae clades, we found that this family of metal-dependent proteinases has been amplified 10 times in the genome of the Araneomorphae/Orbiculariae 
clade. The observed proteolytic effects of metalloproteinases in the venom of some Araneomorphae spiders are probably unrelated to their high expression in the spinning glands. Moreover, until recently, this subfamily of the meprin metalloproteases was believed to exist only in vertebrates, although even more recently, it was reported in the horseshoe crab Limulus polyphemus, an organism from the subphylum Chelicerata. Our work, therefore, corroborates the evidence that this gene family is present in the Arthropoda subphylum studied here. Moreover, KOG data from 2003 have classified a number of these proteins in the genomes of invertebrates such as D. melanogaster and Caenorhabditis elegans. Meprins consist of a single, membrane-anchored member of the astacin family and have been shown to be implicated in a number of complex cellular processes in higher eukaryotes, such as cell migration, immune reactions, and tissue differentiation. A clue to their function may come from some works reporting their relationship to human collagen fibers.