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bioRxiv · 10.1101/2024.09.27.615525

Photosymbiosis Shaped Animal Genome Architecture and Gene Evolution as Revealed in Giant Clams

Li, R.·Leiva, C.·Lemer, S.·Kirkendale, L.·Li, J.
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Abstract

Symbioses are major drivers of organismal diversification and phenotypic innovation. However, how long-term symbioses shape whole genome evolution in metazoans is still underexplored. Here, we used a giant clam (Tridacna maxima) genome to demonstrate how symbiosis has left complex signatures in an animals genome. Giant clams thrive in oligotrophic waters by forming a remarkable association with photosymbiotic dinoflagellate algae. Genome-based demographic inferences uncovered a tight correlation between T. maxima global population change and major paleoclimate and habitat shifts, highlighting how abiotic and biotic factors dictate T. maxima microevolution. Comparative analyses revealed unique symbiosis-driven genomic features, including expansion and contraction of immunity-related gene families and a large proportion of lineage-specific genes. Strikingly, about 70% of the genome is composed of repetitive elements, especially transposable elements, most likely resulting from a symbiosis-adapted immune system. This work greatly enhances our understanding of genomic drivers of symbiosis that underlie metazoan evolution and diversification.

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Li, R., Leiva, C., Lemer, S., Kirkendale, L., Li, J.. 2024-09-30. Photosymbiosis Shaped Animal Genome Architecture and Gene Evolution as Revealed in Giant Clams. https://doi.org/10.1101/2024.09.27.615525

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