v.1.0 (September 20, 2007): The assembly release version 1.0 of whole genome shotgun reads was constructed with the JGI assembler, Jazz, using paired end sequencing reads at a coverage of 7.92x. After trimming for vector and quality, 2,354,463 reads assembled into 1993 scaffolds totaling 235.4 Mbp. Roughly half of the genome is contained in 21 scaffolds all at least 3.1 Mbp in length.

The current draft release includes a total of 23,432 gene models predicted using the JGI annotation pipeline. This data set is composed of gene models built by homology to known proteins from other model organisms and ab initio gene predictions as well as from available Helobdella robusta EST and cDNA data. Approximately 94.8% of the ESTs/cDNAs mapped to the v.1.0 assembly. Average gene length is 3.9 kb and average transcript length is 1.2 kb, with the average protein containing 376 amino acids. There are approximately 6.12 exons per gene averaging 206 bp each with intron spacing of 526 bp. Gene functions have been automatically assigned based on homology to known genes.