Chromosome-level genome assembly of the razor clam Sinonovacula constricta (Lamarck, 1818)

Bivalves, a highly diverse and the most evolutionarily successful class of
invertebrates native to aquatic habitats, provide valuable molecular
resources for understanding the evolutionary adaptation and aquatic
ecology. Here we reported a high-quality chromosome-level genome assembly
of the razor clam Sinonovacula constricta using Pacific Bioscience
single-molecule real-time sequencing, Illumina paired-end sequencing, 10X
Genomics linked-reads and Hi-C reads. The genome size was 1,220.85 Mb,
containing scaffold N50 of 65.93 Mb and contig N50 of 976.94 Kb. A total
of 899 complete (91.92%) and seven partial (0.72%) matches of the 978
metazoa Benchmarking Universal Single-Copy Orthologs were determined in
this genome assembly. And Hi-C scaffolding of the genome resulted in 19
pseudochromosomes. A total of 28,594 protein-coding genes were predicted
in the S. constricta genome, of which 25,413 genes (88.88%) were
functionally annotated. In addition, 39.79% of the assembled genome was
composed of repetitive sequences, and 4,372 non-coding RNAs were
identified. The enrichment analyses of the significantly expanded and
contracted genes suggested an evolutionary adaptation of S. constricta to
highly stressful living environments. In summary, the genomic resources
generated in this work not only provide a valuable reference genome for
investigating the molecular mechanisms of S. constricta biological
functions and evolutionary.