Scientists decode genome of ocean diatom, unlocking clues to marine productivity
Researchers have sequenced the first high-quality genome of Chaetoceros muelleri, a dominant ocean microalgae responsible for roughly one-tenth of global oxygen production. The findings reveal how these organisms rapidly evolved specialized genes for nutrient uptake and stress response—insights that could inform efforts to harness algae for biofuels, carbon capture, and sustainable food production.
Originaltitel: A High-Quality Genome Assembly of <i>Chaetoceros muelleri</i> Reveals Extensive Gene Duplication, Functional Diversification, and Unique Lineage-Specific Innovation
Abstract Diatoms are major contributors to marine primary production, yet high-quality nuclear genome resources remain scarce for ecologically dominant lineages such as Chaetoceros . Here, we present the first high-quality nuclear genome assembly of Chaetoceros muelleri , generated from living cells resurrected from resting spores preserved in Baltic Sea sediments and sequenced using PacBio HiFi long-read technology. The assembly is compact (43□Mb), highly contiguous (N50□=□1.40□Mb), and highly complete (93% BUSCO). Comparative analyses across 14 diatom genomes revealed extensive lineage-specific and expanded gene families in C. muelleri , alongside a small, conserved core genome, reflecting rapid evolutionary turnover. Functional enrichment highlighted diversification of polysaccharide biosynthesis, vesicle-mediated trafficking, membrane remodelling, and transcriptional regulation, consistent with adaptations linked to frustule formation and environmental responsiveness. Transposable elements (TEs) strongly shape the genome, accounting for ∼18% of the assembly, with dominant LTR retrotransposons and a large fraction of unclassified repeats suggesting novel or highly diverged TE lineages. Enrichment of DNA replication, recombination, and repair functions further indicates compensatory genome maintenance associated with TE-driven structural dynamics. Direct comparison with C. tenuissimus revealed contrasting patterns of gene family expansion and regulatory innovation, underscoring divergent evolutionary strategies within Chaetoceros . By integrating resurrection ecology with long-read genomics, this study provides a foundational genomic resource for C. muelleri and highlights the role of TE-mediated genome plasticity in diatom evolution.