Whole-genome in-silico subtractive hybridization (WISH) - using massive sequencing for the identification of unique and repetitive sex-specific sequences: the example of Schistosoma mansoni.

Julien Portela (1) , Christoph Grunau (1) , Celine Cosseau (1) , Sophie Beltran (1) , Christelle Dantec (2) , Hugues Parrinello (2) , Jerome Boissier (1)

1 BETM - Biologie et écologie tropicale et méditerranéenne [2007-2010]
2 IGF MGX - Institut de Génomique Fonctionnelle - Montpellier GenomiX

Emerging methods of massive sequencing that allow for rapid re-sequencing of entire genomes at comparably low cost are changing the way biological questions are addressed in many domains. Here we propose a novel method to compare two genomes (genome-to-genome comparison). We used this method to identify sex-specific sequences of the human blood fluke Schistosoma mansoni. RESULTS: Genomic DNA was extracted from male and female (heterogametic) S. mansoni adults and sequenced with a Genome Analyzer (Illumina). Sequences are available at the NCBI sequence read archive (http://www.ncbi.nlm.nih.gov/Traces/sra/) under study accession number SRA012151.6. Sequencing reads were aligned to the genome, and a pseudogenome composed of known repeats. Straightforward comparative bioinformatics analysis was performed to compare male and female schistosome genomes and identify female-specific sequences. We found that the S. mansoni female W chromosome contains only few specific unique sequences (950 Kb i.e. about 0.2% of the genome). The majority of W-specific sequences are repeats (10.5 Mb i.e. about 2.5% of the genome). Arbitrarily selected W-specific sequences were confirmed by PCR. Primers designed for unique and repetitive sequences allowed to reliably identify the sex of both larval and adult stages of the parasite. CONCLUSION: Our genome-to-genome comparison method that we call "whole-genome in-silico subtractive hybridization" (WISH) allows for rapid identification of sequences that are specific for a certain genotype (e.g. the heterogametic sex). It can in principle be used for the detection of any sequence differences between isolates (e.g. strains, pathovars) or even closely related species.

Domaines: Biodiversité et Ecologie

Julien Portela, Christoph Grunau, Celine Cosseau, Sophie Beltran, Christelle Dantec, et al.. Whole-genome in-silico subtractive hybridization (WISH) - using massive sequencing for the identification of unique and repetitive sex-specific sequences: the example of Schistosoma mansoni.. BMC Genomics, 2010, 11 (1), pp.387. ⟨10.1186/1471-2164-11-387⟩. ⟨halsde-00495369⟩