Genomic insights into the adaptation and evolution of the Nautilus, an ancient but evolving "living fossil".

The nautilus, commonly known as a "living fossil," is endangered and may be at risk of extinction. The lack of genomic information hinders a thorough understanding of the biology and evolution of nautilus, which can shed light on the conservation of this endangered species. Here, we report the first high-quality chromosome-level genome assembly of Nautilus pompilius. The assembled genome size comprised 785.15 Mb. Comparative genomic analyses indicated that transposable elements (TEs) and large-scale genome reorganizations may have driven lineage-specific evolution in the cephalopods. Remarkably, evolving conserved genes and recent TE insertion activities were identified in N. pompilius, and we speculate that these findings reflect the strong adaptability and high survival of the nautilus. Besides, we also identified gene families that are potentially responsible for specific adaptation and evolution events. Our study provides unprecedented insights into the specialized biology and evolution of the N. pompilius, and the results serve as an important resource for future conservation genomics of the nautilus and its closely related species.