Transcriptomic analysis of the polyploid adriatic sturgeon, Acipenser naccarii

The 454 sequencing of four normalised cDNA libraries from gonads and brain of A naccarii, yielded 182,066 and 167,776 reads for male and female libraries respectively, which after a strict quality control were iteratively assembled together, giving more then 55,000 high quality Expressed sequence tags (ESTs). It was estimated the joint assembly of A. naccarii was able to cover about 80% of its total transcripts expressed in both gonad and brain with a mean contigs coverage of 4X. The Multi-step annotation process finally results in 16% successfully annotated sequences, with GO terms. the transcriptomes were screened for 32 sex related genes and highlighted 5 and 2 genes that are potentially specifically expressed in male and female, at the first life stage at which sex is histologically identifiable. The transcriptomes were also compared with those of other fish species for which relevant genomic informations were available. Finally, 21,791 putative EST-linked Single Nucleotide Polymorphisms (SNPs) and 5,295 Single Sequence Repeats (SSRs) was identified in A. naccarii. This study represents the first characterisation of transcriptomes from an high endangered sturgeon species