De novo characterization of the gene-rich transcriptomes of two color-polymorphic spiders, Theridion grallator and T. californicum (Araneae: Theridiidae), with special reference to pigment genes

BMC Genomics

Research Article

Geoff S Oxford¹  Michael S Brewer²  Rosemary G Gillespie²  Peter JP Croucher²  Christopher J Winchell³ 

[1]Department of Biology (E019), University of York, Wentworth Way, YO10 5DD, Heslington, York, UK

[2]Department of Environmental Science, Policy and Management, University of California, 94720-3114, Berkeley, CA, USA

[3]Department of Molecular and Cell Biology, University of California, 94720-3200, Berkeley, CA, USA

关键词: Araneae;    Spider;    Color;    Pigmentation;    Polymorphism;    Pteridine;    Ommochrome;    RNA-seq;    cDNA;   

DOI  :  10.1186/1471-2164-14-862

 received in 2012-12-18, accepted in 2013-11-25,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundA number of spider species within the family Theridiidae exhibit a dramatic abdominal (opisthosomal) color polymorphism. The polymorphism is inherited in a broadly Mendelian fashion and in some species consists of dozens of discrete morphs that are convergent across taxa and populations. Few genomic resources exist for spiders. Here, as a first necessary step towards identifying the genetic basis for this trait we present the near complete transcriptomes of two species: the Hawaiian happy-face spider Theridion grallator and Theridion californicum. We mined the gene complement for pigment-pathway genes and examined differential expression (DE) between morphs that are unpatterned (plain yellow) and patterned (yellow with superimposed patches of red, white or very dark brown).ResultsBy deep sequencing both RNA-seq and normalized cDNA libraries from pooled specimens of each species we were able to assemble a comprehensive gene set for both species that we estimate to be 98-99% complete. It is likely that these species express more than 20,000 protein-coding genes, perhaps 4.5% (ca. 870) of which might be unique to spiders. Mining for pigment-associated Drosophila melanogaster genes indicated the presence of all ommochrome pathway genes and most pteridine pathway genes and DE analyses further indicate a possible role for the pteridine pathway in theridiid color patterning.ConclusionsBased upon our estimates, T. grallator and T. californicum express a large inventory of protein-coding genes. Our comprehensive assembly illustrates the continuing value of sequencing normalized cDNA libraries in addition to RNA-seq in order to generate a reference transcriptome for non-model species. The identification of pteridine-related genes and their possible involvement in color patterning is a novel finding in spiders and one that suggests a biochemical link between guanine deposits and the pigments exhibited by these species.

【 授权许可】

CC BY   
© Croucher et al.; licensee BioMed Central Ltd. 2013