Sex-Related Genes Obtained by Pyrosequencing 454 and cDNA Library in Red Abalone (H. rufescens)

Ontology analysis was carried out to identify sex-related genes in red abalone. 454 pyrosequencing and a cDNA library construction were performed with gonadal tissue from both sexes of mature abalones. A total of 214,206 sequences was obtained by 454 pyrosequencing grouped into 21,606 contigs and 28,460 singletons. For the cDNA library, we obtained a total of 1,023 sequences grouped in 79 contigs and 663 singletons. BLASTx analysis (E value ≤ 10^-6 and ≥ 33% similarity) showed that 44.12% of the 454 pyrosequencing contigs and 22.78% of the contigs of the cDNA library had homology with the protein database (nr) at NCBI. However, the databases of Gene Ontology (GO), ANNEX and InterPro Scan (IPS), counted 61.97% of 454 pyrosequencing sequences and 56.7% for the cDNA library. The ontological analysis showed that 1.84 and 2.54% of the contigs for 454 pyrosequencing and cDNA library were associated with reproductive processes, respectively. In this sense, the sex-related genes found in red abalone included the sperm lysin precursor and vitellogenin associated with the cDNA library. For 454 pyrosequencing, genes associated with male were fertilization protein, sperm lysin precursor, tektins, axonemal proteins, sperm proteins, spermidine, among others, while the genes associated with female were vitellogenin, vitelline envelope zona pellucida domain 4 and 10, vitelline envelope sperm lysin partial and sperm associated antigens. This work open the possibilities to study different aspects of sexual reproduction in abalone, since this organism mature in early time of their lives impacting in a negative way by reducing the growth rate.