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A toxicogenomic approach was used for toxicity evaluation of arsenic in the aquatic environment, and differential gene expression was investigated from 24 h and 96 h water-only acute toxicity tests with the aquatic oligochaete, Tubifex tubifex (Annelida, Clitellata). Several toxicological endpoints (survival and autotomy) of the oligochaete and tissue residues were measured, and dose-response modelling of gene expression data was studied. A reference transcriptome of the aquatic oligochaete, T. tubifex, was reconstructed for the first time, and genes related to cell stress response (Hsc70, Hsp10, Hsp60, and Hsp83), energy metabolism (COX1), oxidative stress (Cat, GSR, and MnSOD), and the genes involved in the homeostasis of organisms (CaM, RpS13, and UBE2) were identified and characterised. The potential use of the genes identified for risk assessment in freshwater ecosystems as early biomarkers of arsenic toxicity is discussed. [ABSTRACT FROM AUTHOR]

Background: The continuous use of the herbicides contributes to the emergence of the resistant populations of numerous weed species that are tolerant to multiple herbicides with different modes of action (multiple resistance) which is provided by non‐target‐site resistance mechanisms. In this study, we addressed the question of rapid acquisition of herbicide resistance to pinoxaden (acetyl CoA carboxylase inhibitor) in Apera spica‐venti, which endangers winter cereal crops and has high adaptation capabilities to inhabit many rural locations. To this end, de novo transcriptome of Apera spica‐venti was assembled and RNA‐sequencing analysis of plants resistant and susceptible to pinoxaden treated with this herbicide was performed. Results: The obtained data showed that the prime candidate genes responsible for herbicide resistance were those encoding 3‐ketoacyl‐CoA synthase 12‐like, UDP‐glycosyltransferases (UGT) including UGT75K6, UGT75E2, UGT83A1‐like, and glutathione S‐transferases (GSTs) such as GSTU1 and GSTU6. Also, such highly accelerated herbicide resistance emergence may result from the enhanced constitutive expression of a wide range of genes involved in detoxification already before herbicide treatment and may also influence response to biotic stresses, which was assumed by the detection of expression changes in genes encoding defence‐related proteins, including receptor kinase‐like Xa21. Moreover, alterations in the expression of genes associated with methylation in non‐treated herbicide‐resistant populations were identified. Conclusion: The obtained results indicated genes that may be involved in herbicide resistance. Moreover, they provide valuable insight into the possible effect of resistance on the weed interaction with the other stresses by indicating pathways associated with both abiotic and biotic stresses. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Douglas-fir (Pseudotsuga menziesii) is native to western North America. It grows in a wide range of environmental conditions and is an important timber tree. Although there are several studies on the gene expression responses of Douglas-fir to abiotic cues, the absence of highquality transcriptome and genome data is a barrier to further investigation. Like for most conifers, the available transcriptome and genome reference dataset for Douglas-fir remains fragmented and requires refinement. We aimed to generate a highly accurate, and complete reference transcriptome and genome annotation. We deep-sequenced the transcriptome of Douglas-fir needles from seedlings that were grown under nonstress control conditions or a combination of heat and drought stress conditions using long-read (LR) and short-read (SR) sequencing platforms. We used 2 computational approaches, namely de novo and genome-guided LR transcriptome assembly. Using the LR de novo assembly, we identified 1.3X more high-quality transcripts, 1.85X more "complete" genes, and 2.7X more functionally annotated genes compared to the genome-guided assembly approach. We predicted 666 long noncoding RNAs and 12,778 unique protein-coding transcripts including 2,016 putative transcription factors. We leveraged the LR de novo assembled transcriptome with pairedend SR and a published single-end SR transcriptome to generate an improved genome annotation. This was conducted with BRAKER2 and refined based on functional annotation, repetitive content, and transcriptome alignment. This high-quality genome annotation has 51,419 unique gene models derived from 322,631 initial predictions. Overall, our informatics approach provides a new reference Douglas-fir transcriptome assembly and genome annotation with considerably improved completeness and functional annotation. [ABSTRACT FROM AUTHOR]

The raphidophyte Heterosigma akashiwo is a harmful algal species. The bloom of this organism has been associated with the massive mortality of fish in many coastal waters. To investigate the molecular mechanism of H. akashiwo blooms, having a reliable reference transcriptome of this species is essential. Therefore, in this study, a full-length transcriptome of H. akashiwo was obtained by single-molecule real-time sequencing. In total, 45.44 Gb subread bases were generated, and 16,668 unigenes were obtained after the sequencing data processing. A total of 8666 (52.00%) unigenes were successfully annotated using seven public databases. Among them, mostly phosphorus and nitrogen metabolism genes were detected. Moreover, there were 300 putative transcription factors, 4392 putative long non-coding RNAs, and 7851 simple sequence repeats predicted. This study provides a valuable reference transcriptome for understanding how H. akashiwo blooms at a molecular level. [ABSTRACT FROM AUTHOR]

Simple Summary: The honeybee is an economically and ecologically essential insect species and a critical social behavior model. It is vital to honey production and pollination. Therefore, it has been studied extensively in entomological research. The Western honeybee (Apis mellifera) is a representative species of honeybees. Reference transcriptome data are required to perform the meta-analyses using public RNA-Seq data and transcriptome analysis using newly sequenced RNA-Seq data. The reference transcriptome sequences were constructed, which consisted of 149,685 transcripts, and 194,174 predicted amino acid sequences. Half the predicted protein sequences were functionally annotated using protein sequence datasets for several model and insect species. We performed meta-analysis to search for novel immune-response-related transcripts. We identified 3–20 transcripts that were upregulated or downregulated in response to both viral and bacterial infections. However, the immune-related transcripts were not included among them. Autophagy-related protein 3 was downregulated by viral infections. The results suggested that autophagy was implicated in the viral immune responses, and autophagy was not regulated by the canonical immune pathways in A. mellifera. The results of the meta-analysis suggested that the reference transcriptome data could be used for transcriptome analysis in A. mellifera. The Western honeybee (Apis mellifera) is valuable in biological research and agriculture. Its genome sequence was published before those for other insect species. RNA-Seq data for A. mellifera have been applied in several recently published studies. Nevertheless, these data have not been prepared for use in subsequent meta-analyses. To promote A. mellifera transcriptome analysis, we constructed reference transcriptome data using the reference genome sequence and RNA-Seq data curated from about 1,000 runs of public databases. The new reference transcriptome data construct comprised 149,685 transcripts, and 194,174 protein sequences were predicted. Approximately 50–60% of the predicted protein sequences were functionally annotated using the protein sequence data for several model and insect species. Novel candidate immune-related transcripts were searched by meta-analysis using immune-response-related RNA-Seq and reference transcriptome data. Three to twenty candidate transcripts including autophagy-related protein 3 were upregulated or downregulated in response to both viral and bacterial infections. The constructed reference transcriptome data may facilitate future transcriptome analyses of A. mellifera. [ABSTRACT FROM AUTHOR]

The raphidophyte Heterosigma akashiwo is a harmful algal species. The bloom of this organism has been associated with the massive mortality of fish in many coastal waters. To investigate the molecular mechanism of H. akashiwo blooms, having a reliable reference transcriptome of this species is essential. Therefore, in this study, a full-length transcriptome of H. akashiwo was obtained by single-molecule real-time sequencing. In total, 45.44 Gb subread bases were generated, and 16,668 unigenes were obtained after the sequencing data processing. A total of 8666 (52.00%) unigenes were successfully annotated using seven public databases. Among them, mostly phosphorus and nitrogen metabolism genes were detected. Moreover, there were 300 putative transcription factors, 4392 putative long non-coding RNAs, and 7851 simple sequence repeats predicted. This study provides a valuable reference transcriptome for understanding how H. akashiwo blooms at a molecular level.

The Western honeybee (Apis mellifera) is valuable in biological research and agriculture. Its genome sequence was published before those for other insect species. RNA-Seq data for A. mellifera have been applied in several recently published studies. Nevertheless, these data have not been prepared for use in subsequent meta-analyses. To promote A. mellifera transcriptome analysis, we constructed reference transcriptome data using the reference genome sequence and RNA-Seq data curated from about 1,000 runs of public databases. The new reference transcriptome data construct comprised 149,685 transcripts, and 194,174 protein sequences were predicted. Approximately 50–60% of the predicted protein sequences were functionally annotated using the protein sequence data for several model and insect species. Novel candidate immune-related transcripts were searched by meta-analysis using immune-response-related RNA-Seq and reference transcriptome data. Three to twenty candidate transcripts including autophagy-related protein 3 were upregulated or downregulated in response to both viral and bacterial infections. The constructed reference transcriptome data may facilitate future transcriptome analyses of A. mellifera.

Climate change and ocean warming threaten the persistence of corals worldwide. Genomic resources are critical to study the evolutionary trajectory, adaptive potential, and genetic distinctiveness of coral species. Here, we provide a reference genome of the cauliflower coral Pocillopora verrucosa , a broadly prevalent reef-building coral with important ecological roles in the maintenance of reefs across the Red Sea, the Indian Ocean, and the Pacific Ocean. The genome has an assembly size of 380,505,698 bp with a scaffold N50 of 333,696 bp and a contig N50 of 75,704 bp. The annotation of the assembled genome returned 27,439 gene models of which 89.88% have evidence of transcription from RNA-Seq data and 97.87% show homology to known genes. A high proportion of the genome (41.22%) comprised repetitive elements in comparison to other cnidarian genomes, in particular in relation to the small genome size of P. verrucosa. [ABSTRACT FROM AUTHOR]

Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. The worldwide demand for high-quality gonads of this species has addressed the depletion of its natural populations. Studies on this sea urchin are limited, and genomic information is almost nonexistent. Hence, generate a transcriptome is crucial information that will considerably enrich molecular data and promote future findings for the L. albus aquaculture. Here, we obtained transcriptomic data of the edible red sea urchin by Illumina platform. Total RNA was extracted from gonads, intestines, and coelomocytes of juvenile urchins, and samples were sequenced using MiSeq Illumina technology. A total of 91,119,300 paired-end reads were de novo assembled, 185,239 transcripts produced, and a reference transcriptome created with 38.8% GC content and an N50 of 1769 bp. Gene ontology analysis revealed notable differences in the expression profiles between gonads, intestines, and coelomocytes, allowing the detection of transcripts associated with specific biological processes and KEGG pathways. These data were validated using 12 candidate transcripts by real-time qPCR. This dataset will provide a valuable molecular resource for L. albus and other species of sea urchins.

Coconut, Cocos nucifera L., is widely cultivated for its edible and non-edible products. In the Philippines, the traditional coconut variety, Laguna Tall (LAGT), exhibits good genetic potential as a pure population or as open-pollinated variety (OPV). It was the male parent of the first PCA-recommended hybrid. Because of its importance in agronomic breeding, efforts are geared towards increasing genetic resources through genome and transcriptome sequencing. Here, pooled total RNA from leaves, nuts, and flowers of mature stage LAGT was sequenced using Illumina HiSeq 2000, followed by de novo assembly using four different transcriptome assemblers: Trinity, SOAPdenovo-Trans, Trans-Abyss, and Velvet-Oases. Each assembly was evaluated for accuracy using RSEM-EVAL, a reference-free evaluation method for transcript abundance data. Trans-Abyss outperformed the other three assemblers, but to have a better representation of the LAGT transcriptome, assemblies generated by the four programs were combined using the Evidential Gene tr2aacds pipeline. A total of 79,263 transcripts were generated from the combined transcriptomes. Also, Fragments Per Kilobase of transcript per Million mapped read (FPKM) units were used to quantify in silico gene expression. A total of 68,147 transcripts were generated by RSEM and compared against the CDD, Trembl, and UniProt databases. Gene ontology (GO) analysis and KEGG classification revealed that up to 33.8% of LAGT genes are involved in protein modification. The top 20 expressed genes were annotated using the nr database, which revealed that the most highly expressed transcript is a novel transcript. Microsatellite markers were also obtained for future use as breeding tools. Overall, this study provides a comprehensive assembly of the Cocos nucifera L. transcriptome useful as a molecular toolbox to identify key factors involved in important biological and cellular processes in coconut. [ABSTRACT FROM AUTHOR]

Summary: Zinc (Zn) hyperaccumulation and hypertolerance are highly variable traits in Arabidopsis halleri. Metallicolous populations have evolved from nearby nonmetallicolous populations in multiple independent adaptation events. To determine whether these events resulted in similar or divergent adaptive strategies to high soil Zn concentrations, we compared two A. halleri metallicolous populations from distant genetic units in Europe (Poland (PL22) and Italy (I16)). The ionomic (Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP‐AES)) and transcriptomic (RNA sequencing (RNA‐Seq)) responses to growth at 5 and 150 μM Zn were analyzed in root and shoot tissues to examine the contribution of the geographic origin and treatment to variation among populations. These analyses were enabled by the generation of a reference A. halleri transcriptome assembly. The genetic unit accounted for the largest variation in the gene expression profile, whereas the two populations had contrasting Zn accumulation phenotypes and shared little common response to the Zn treatment. The PL22 population displayed an iron deficiency response at high Zn in roots and shoots, which may account for higher Zn accumulation. By contrast, I16, originating from a highly Zn‐contaminated soil, strongly responded to control conditions. Our data suggest that distinct mechanisms support adaptation to high Zn in soils among A. halleri metallicolous populations. [ABSTRACT FROM AUTHOR]

A transcriptomics approach was chosen in order to determine candidate genes for metabolic herbicide resistance in a quantitative comparison of expressed genes in sensitive wild type and resistant blackgrass (Alopecurus myosuroides = ALOMY) plants. Firstly a reference transcriptome for blackgrass was established by means of a paired-end RNA-Seq protocol prepared from control and herbicide treated plants from a metabolic resistant biotype. Secondly gene expression was measured in different metabolic resistant ALOMY biotypes and a representative selection of sensitive wild type plants using a 3´-specific RNA sequencing strategy and related to the reference transcriptome. By comparing expression levels for individual genes in wild type and resistant blackgrass biotypes candidate genes from the group of glutathione transferases were identified. Further analyses will be necessary in order to verify a close correlation with the metabolic resistance.

High Throughput Sequencing capabilities have made the process of assembling a transcriptome easier, whether or not there is a reference genome. But the quality of a transcriptome assembly must be good enough to capture the most comprehensive catalog of transcripts and their variations, and to carry out further experiments on transcriptomics. There is currently no consensus on which of the many sequencing technologies and assembly tools are the most effective. Many non-model organisms lack a reference genome to guide the transcriptome assembly. One question, therefore, is whether or not a reference-based genome assembly gives better results than de novo assembly. The blood-sucking insect Rhodnius prolixus —a vector for Chagas disease—has a reference genome. It is therefore a good model on which to compare reference-based and de novo transcriptome assemblies. In this study, we compared de novo and reference-based genome assembly strategies using three datasets (454, Illumina, 454 combined with Illumina) and various assembly software. We developed criteria to compare the resulting assemblies: the size distribution and number of transcripts, the proportion of potentially chimeric transcripts, how complete the assembly was (completeness evaluated both through CEGMA software and R. prolixus proteome fraction retrieved). Moreover, we looked for the presence of two chemosensory gene families (Odorant-Binding Proteins and Chemosensory Proteins) to validate the assembly quality. The reference-based assemblies after genome annotation were clearly better than those generated using de novo strategies alone. Reference-based strategies revealed new transcripts, including new isoforms unpredicted by automatic genome annotation. However, a combination of both de novo and reference-based strategies gave the best result, and allowed us to assemble fragmented transcripts. [ABSTRACT FROM AUTHOR]

Background: Draft and complete genome sequences from bacteria are key tools to understand genetic determinants involved in pathogenesis in several disease models. Piscirickettsia salmonis is a Gram-negative bacterium responsible for the Salmon Rickettsial Syndrome (SRS), a bacterial disease that threatens the sustainability of the Chilean salmon industry. In previous reports, complete and draft genome sequences have been generated and annotated. However, the lack of transcriptome data underestimates the genetic potential, does not provide information about transcriptional units and contributes to disseminate annotation errors. Results: Here we present the draft genome and transcriptome sequences of four P. salmonis strains. We have identified the transcriptional architecture of previously characterized virulence factors and trait-specific genes associated to cation uptake, metal efflux, antibiotic resistance, secretion systems and other virulence factors. Conclusions: This data has provided a refined genome annotation and also new insights on the transcriptional structures and coding potential of this fish pathogen. [ABSTRACT FROM AUTHOR]

Abstract: The sea bass Dicentrarchus labrax is the center of interest of an increasing number of basic or applied research investigations, even though few genomic or transcriptomic data is available. Current public data only represent a very partial view of its transcriptome. To fill this need, we characterized brain and liver transcriptomes in a generalist manner that would benefit the entire scientific community. We also tackled some bioinformatics questions, related to the effect of RNA fragment size on the assembly quality. Using Illumina RNA-seq, we sequenced organ pools from both wild and farmed Atlantic and Mediterranean fishes. We built two distinct cDNA libraries per organ that only differed by the length of the selected mRNA fragments. Efficiency of assemblies performed on either or both fragments size differed depending on the organ, but remained very close reflecting the quality of the technical replication. We generated more than 19,538Mbp of data. Over 193million reads were assembled into 35,073 contigs (average length=2374bp; N50 =3257). 59% contigs were annotated with SwissProt, which corresponded to 12,517 unique genes. We compared the Gene Ontology (GO) contig distribution between the sea bass and the tilapia. We also looked for brain and liver GO specific signatures as well as KEGG pathway coverage. 23,050 putative micro-satellites and 134,890 putative SNPs were identified. Our sampling strategy and assembly pipeline provided a reliable and broad reference transcriptome for the sea bass. It constitutes an indisputable quantitative and qualitative improvement of the public data, as it provides 5 times more base pairs with fewer and longer contigs. Both organs present unique signatures consistent with their specific physiological functions. The discrepancy in fragment size effect on assembly quality between organs lies in their difference in complexity and thus does not allow prescribing any general strategy. This information on two key organs will facilitate further functional approaches. [Copyright &y& Elsevier]

Background: Next-generation sequencing is providing researchers with a relatively fast and affordable option for developing genomic resources for organisms that are not among the traditional genetic models. Here we present a de novo assembly of the guppy (Poecilia reticulata) transcriptome using 454 sequence reads, and we evaluate potential uses of this transcriptome, including detection of sex-specific transcripts and deployment as a reference for gene expression analysis in guppies and a related species. Guppies have been model organisms in ecology, evolutionary biology, and animal behaviour for over 100 years. An annotated transcriptome and other genomic tools will facilitate understanding the genetic and molecular bases of adaptation and variation in a vertebrate species with a uniquely well known natural history. Results: We generated approximately 336 Mbp of mRNA sequence data from male brain, male body, female brain, and female body. The resulting 1,162,670 reads assembled into 54,921 contigs, creating a reference transcriptome for the guppy with an average read depth of 28×. We annotated nearly 40% of this reference transcriptome by searching protein and gene ontology databases. Using this annotated transcriptome database, we identified candidate genes of interest to the guppy research community, putative single nucleotide polymorphisms (SNPs), and male-specific expressed genes. We also showed that our reference transcriptome can be used for RNA-sequencing-based analysis of differential gene expression. We identified transcripts that, in juveniles, are regulated differently in the presence and absence of an important predator, Rivulus hartii, including two genes implicated in stress response. For each sample in the RNA-seq study, >50% of high-quality reads mapped to unique sequences in the reference database with high confidence. In addition, we evaluated the use of the guppy reference transcriptome for gene expression analyses in a congeneric species, the sailfin molly (Poecilia latipinna). Over 40% of reads from the sailfin molly sample aligned to the guppy transcriptome. Conclusions: We show that next-generation sequencing provided a reliable and broad reference transcriptome. This resource allowed us to identify candidate gene variants, SNPs in coding regions, and sex-specific gene expression, and permitted quantitative analysis of differential gene expression. [ABSTRACT FROM AUTHOR]

Simple Summary: Edible red sea urchin (Loxechinus albus) is an endemic species of echinoderm distributed along the Chilean coasts. This resource has been overexploited in recent years, depleting their natural populations. At present, there are few reported gene sequences available in public databases, restricting the molecular studies associated with aquaculture for this species. The aim of this study was to present the first annotated reference transcriptome of L. albus using NGS technologies and the differential expression transcripts analysis of the evaluated tissues. The transcriptome data obtained in this study will serve as a reference for future molecular research in the edible red sea urchin and other sea urchin species. Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. The worldwide demand for high-quality gonads of this species has addressed the depletion of its natural populations. Studies on this sea urchin are limited, and genomic information is almost nonexistent. Hence, generate a transcriptome is crucial information that will considerably enrich molecular data and promote future findings for the L. albus aquaculture. Here, we obtained transcriptomic data of the edible red sea urchin by Illumina platform. Total RNA was extracted from gonads, intestines, and coelomocytes of juvenile urchins, and samples were sequenced using MiSeq Illumina technology. A total of 91,119,300 paired-end reads were de novo assembled, 185,239 transcripts produced, and a reference transcriptome created with 38.8% GC content and an N50 of 1769 bp. Gene ontology analysis revealed notable differences in the expression profiles between gonads, intestines, and coelomocytes, allowing the detection of transcripts associated with specific biological processes and KEGG pathways. These data were validated using 12 candidate transcripts by real-time qPCR. This dataset will provide a valuable molecular resource for L. albus and other species of sea urchins. [ABSTRACT FROM AUTHOR]

To investigate the immune defense mechanism of Litopenaeus vannamei (L. vannamei) exposed to high concentration of environmental ammonia-N, PacBio full-length transcriptome and Illumina transcriptome sequencing were performed. After ammonia-N exposure, 24,763 and 32,132 full-length transcripts were obtained, while 4465 and 3022 new genes were annotated at 0 and 6 h after compared to L. vannamei whole genome, respectively. Besides, haemocytes transcriptomes, performed at 0, 6 and 48 h, obtained a total of 1017 differentially expressed genes (DEGs), and among them 160 DEGs related to neuroendocrine-immune (NEI) were screened, of which 40 DEGs have alternative splicing form. The following experiments showed that plasma 5-HT and ACh concentrations increased significantly, and then returned to the initial level at 48 h. Moreover, cell membrane receptors (5-HT7R, ACh7R and Toll3), G-protein effectors (AC2 and PLC) and CaM all significantly upregulated, and nuclear transcription factor NF-кB was significantly downregulated, suggesting that 5-HT can act on AC-PKA, PLC - PKC and PLC - CaM pathways through 5-HT7R, and subsequently function on NF-кB together with ACh through ACh7R pathway to affects downstream effector proteins expression. Toll3 pathway is also activated to participate in signal transduction process simultaneously. Furthermore, the expressions of BGBP, PPO3, C-lectin, ALF, LYC and AIF3 were significantly increased, while Syntaxin and Cubilin were significantly decreased. The corresponding immune defense parameters including the THC, PO activity, haemocytes phagocytosis rate, antibacterial and bacteriolytic activities were significantly decreased. All results indicate that after ammonia-N stress, 5-HT, ACh and Toll3 can transfer signal into haemocytes to affect effector proteins and finally reduce immune defense parameters of L. vannamei. This study contributes to better exploration the immune defense mechanism of crustaceans under ammonia-N stress. Unlabelled Image • PacBio full length and Illumina reference transcriptome were performed in L. vannamei under ammsonia-N stress. • Based on transcriptome, 1017 DEGs were obtained and 160 DEGs related to neuroendocrine-immune. • Plasm 5-HT and ACh concentration significantly increased after ammonia-N exposure. • 5-HT, ACh and Toll3 signal transduction pathways were activated and function on NF-кB in haemocytes. • 5-HT, ACh and Toll3 transduced signal into haemocytes to affect effector proteins and then reduced immune defense parameters. [ABSTRACT FROM AUTHOR]

Field crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the field cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection--testis and accessory gland--would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection.