Thirty-six and 37 unique full-length cDNAs from P. marinus and P. chesapeaki, respectively [8] , were used as the queries to nBLASTsearch against P. marinus genomic sequences to obtain the corresponding genomic DNA. The recently published full-length cDNAs and genomic DNAs for proliferating cell nuclear antigen (pcna) and two types of cyclins from P. marinus [14] , as well as 36 other common protein-coding genes of P. marinus such as tubulins, gapdh, centrin, hsp90 and ribosomal proteins reported in GenBank were compared (Table S1 ). Canonical GT/ AG intron/exon boundaries validated the deduced intron start and end positions. The percentage of genes within this cohort that contained introns was determined.