Dataset Information

Transcriptome sequencing of Zhikong scallop (Chlamys farreri) and comparative transcriptomic analysis with Yesso scallop (Patinopecten yessoensis).

ABSTRACT:

Background

Bivalves play an important role in the ecosystems they inhabit and represent an important food source all over the world. So far limited genetic research has focused on this group of animals largely due to the lack of sufficient genetic or genomic resources. Here, we performed de novo transcriptome sequencing to produce the most comprehensive expressed sequence tag resource for Zhikong scallop (Chlamys farreri), and conducted the first transcriptome comparison for scallops.

Results

In a single 454 sequencing run, 1,033,636 reads were produced and then assembled into 26,165 contigs. These contigs were then clustered into 24,437 isotigs and further grouped into 20,056 isogroups. About 47% of the isogroups showed significant matches to known proteins based on sequence similarity. Transcripts putatively involved in growth, reproduction and stress/immune-response were identified through Gene ontology (GO) and KEGG pathway analyses. Transcriptome comparison with Yesso scallop (Patinopecten yessoensis) revealed similar patterns of GO representation. Moreover, 38 putative fast-evolving genes were identified through analyzing the orthologous gene pairs between the two scallop species. More than 46,000 single nucleotide polymorphisms (SNPs) and 350 simple sequence repeats (SSRs) were also detected.

Conclusion

Our study provides the most comprehensive transcriptomic resource currently available for C. farreri. Based on this resource, we performed the first large-scale transcriptome comparison between the two scallop species, C. farreri and P. yessoensis, and identified a number of putative fast-evolving genes, which may play an important role in scallop speciation and/or local adaptation. A large set of single nucleotide polymorphisms and simple sequence repeats were identified, which are ready for downstream marker development. This transcriptomic resource should lay an important foundation for future genetic or genomic studies on C. farreri.

SUBMITTER: Wang S

PROVIDER: S-EPMC3646770 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Publications

Transcriptome sequencing of Zhikong scallop (Chlamys farreri) and comparative transcriptomic analysis with Yesso scallop (Patinopecten yessoensis).

Wang Shan S Hou Rui R Bao Zhenmin Z Du Huixia H He Yan Y Su Hailin H Zhang Yueyue Y Fu Xiaoteng X Jiao Wenqian W Li Yan Y Zhang Lingling L Wang Shi S Hu Xiaoli X

PloS one 20130507 5

<h4>Background</h4>Bivalves play an important role in the ecosystems they inhabit and represent an important food source all over the world. So far limited genetic research has focused on this group of animals largely due to the lack of sufficient genetic or genomic resources. Here, we performed de novo transcriptome sequencing to produce the most comprehensive expressed sequence tag resource for Zhikong scallop (Chlamys farreri), and conducted the first transcriptome comparison for scallops.<h4 ...[more]

PMID: 23667690

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Project description:BackgroundBivalves comprise around 30,000 extant species and have received much attention for their importance in ecosystems, aquaculture and evolutionary studies. Despite the increasing application of real-time quantitative reverse transcription PCR (qRT-PCR) in gene expression studies on bivalve species, little research has been conducted on reference gene selection which is critical for reliable and accurate qRT-PCR analysis. For scallops, systematic evaluation of reference genes that can be used among tissues or embryo/larva stages is lacking, and β-actin (ACT) is most frequently used as qRT-PCR reference gene without validation.ResultsIn this study, 12 commonly used candidate reference genes were selected from the transcriptome data of Yesso scallop (Patinopectenyessoensis) for suitable qRT-PCR reference genes identification. The expression of these genes in 36 tissue samples and 15 embryo/larva samples under normal physiological conditions was examined by qRT-PCR, and their expression stabilities were evaluated using three statistic algorithms, geNorm, NormFinder, and comparative ∆Ct method. Similar results were obtained by the three approaches for the most and the least stably expressed genes. Final comprehensive ranking for the 12 genes combing the results from the three programs showed that, for different tissues, DEAD-box RNA helicase (HELI), ubiquitin (UBQ), and 60S ribosomal protein L16 (RPL16) were the optimal reference genes combination, while for different embryo/larva stages, gene set containing Cytochrome B (CB), Cytochrome C (CC), Histone H3.3 (His3.3), and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were recommended for qRT-PCR normalization. ACT was among the least stable genes for both adult tissues and embryos/larvae.ConclusionsThis work constitutes the first systematic analysis on reference genes selection for qRT-PCR normalization in scallop under normal conditions. The suitable reference genes we recommended will be useful for the identification of genes related to biological processes in Yesso scallop, and also in the reference gene selection for other scallop or bivalve species.

Project description:The Yesso scallop Patinopecten yessoensis is an economically important marine bivalve species in aquaculture and fishery in Asian countries. However, limited genomic resources are available for this scallop, which hampers investigations into molecular mechanisms underlying their unique biological characteristics, such as shell formation and pigmentation. Mantle is the special tissue of P. yessoensis that secretes biomineralization proteins inducing shell deposition as well as pigmentation on the shells. However, a current deficiency of transcriptome information limits insight into mechanisms of shell formation and pigmentation in this species. In this study, the transcriptome of the mantle of P. yessoensis was deeply sequenced and characterized using Illumina RNA-seq technology. A total of 86,521 unique transcripts are assembled from 55,884,122 reads that passed quality filters, and annotated, using Gene Ontology classification. A total of 259 pathways are identified in the mantle transcriptome, including the calcium signaling and melanogenesis pathways. A total of 237 unigenes that are homologous to 102 reported biomineralization genes are identified, and 121 unigenes that are homologous to 93 known proteins related to melanin biosynthesis are found. Twenty-three annotated unigenes, which are mainly homologous to calmodulin and related proteins, Ca2+/calmodulin-dependent protein kinase, adenylate/guanylate cyclase, and tyrosinase family are potentially involved in both biomineralization and melanin biosynthesis. It is suggested that these genes are probably not limited in function to induce shell deposition by calcium metabolism, but may also be involved in pigmentation of the shells of the scallop. This potentially supports the idea that there might be a link between calcium metabolism and melanin biosynthesis, which was previously found in vertebrates. The findings presented here will notably advance the understanding of the sophisticated processes of shell formation as well as shell pigmentation in P. yessoensis and other bivalve species, and also provide new evidence on gene expression for the understanding of pigmentation and biomineralization not only in invertebrates but also probably in vertebrates.

Project description:BackgroundThe Yesso scallop, Patinopecten (Mizuhopecten) yessoensis, is a commercially important bivalve in the coastal countries of Northeast Asia. It has complex modes of sex differentiation, but knowledge of the mechanisms underlying this sex determination and differentiation is limited.ResultsIn this study, the gonad tissues from females and males at three developmental stages were used to investigate candidate genes and networks for sex differentiation via RNA-Req. A total of 901,980,606 high quality clean reads were obtained from 18 libraries, of which 417 expressed male-specific genes and 754 expressed female-specific genes. Totally, 10,074 genes differentially expressed in females and males were identified. Weighted gene co-expression network analysis (WGCNA) revealed that turquoise and green gene modules were significantly positively correlated with male gonads, while coral1 and black modules were significantly associated with female gonads. The most important gene for sex determination and differentiation was Pydmrt 1, which was the only gene discovered that determined the male sex phenotype during early gonadal differentiation. Enrichment analyses of GO terms and KEGG pathways revealed that genes involved in metabolism, genetic and environmental information processes or pathways are sex-biased. Forty-nine genes in the five modules involved in sex differentiation or determination were identified and selected to construct a gene co-expression network and a hypothesized sex differentiation pathway.ConclusionsThe current study focused on screening genes of sex differentiation in Yesso scallop, highlighting the potential regulatory mechanisms of gonadal development in P. yessoensis. Our data suggested that WCGNA can facilitate identification of key genes for sex differentiation and determination. Using this method, a hypothesized P. yessoensis sex determination and differentiation pathway was constructed. In this pathway, Pydmrt 1 may have a leading function.

Dataset Information

Transcriptome sequencing of Zhikong scallop (Chlamys farreri) and comparative transcriptomic analysis with Yesso scallop (Patinopecten yessoensis).

Background

Results

Conclusion

Publications

Transcriptome sequencing of Zhikong scallop (Chlamys farreri) and comparative transcriptomic analysis with Yesso scallop (Patinopecten yessoensis).

Similar Datasets

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