Publication Date
9-11-2025
Document Type
Article
Publication Title
Molecular Biology and Evolution
Volume
42
Issue
10
DOI
10.1093/molbev/msaf219
Abstract
Antifreeze proteins (AFPs) have enabled teleost fishes to repeatedly colonize polar seas. Four AFP types have convergently evolved in several fish lineages. AFPs inhibit ice crystal growth and lower tissue freezing point. In lineages with AFPs, species inhabiting colder environments may possess more AFP copies. Elucidating how differences in AFP copy number evolve is challenging due to the genes' tandem array structure and consequently poor resolution of these repetitive regions. Here, we explore the evolution of type III AFPs (AFP III) in the globally distributed suborder Zoarcoidei, leveraging six new long-read genome assemblies. Zoarcoidei has fewer genomic resources relative to other polar fish clades while it is one of the few groups of fishes adapted to both the Arctic and Southern Oceans. Combining these new assemblies with additional long-read genomes available for Zoarcoidei, we conducted a comprehensive phylogenetic test of AFP III evolution and modeled the effects of thermal habitat and depth on AFP III gene family evolution. We confirm a single origin of AFP III via neofunctionalization of the enzyme sialic acid synthase B. We also show that AFP copy number increased under low temperature but decreased with depth, potentially because pressure lowers freezing point. Associations between the environment and AFP III copy number were driven by duplications of paralogs that were translocated out of the ancestral locus at which AFP III arose. Our results reveal novel environmental effects on AFP evolution and demonstrate the value of high-quality genomic resources for studying how structural genomic variation shapes convergent adaptation.
Funding Number
TMS2020TMT13
Funding Sponsor
Washington State University
Keywords
adaptation, antifreeze protein, gene copy number, genomics, long-read sequencing, temperature
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Moss Landing Marine Laboratories
Recommended Citation
Samuel N. Bogan, Nathan Surendran, Scott Hotaling, Thomas Desvignes, Iliana Bista, Luana S.F. Lins, Mari H. Eilertsen, Nathalie R. Le François, Tait Algayer, Scott L. Hamilton, Paul B. Frandsen, Federico G. Hoffmann, and Joanna L. Kelley. "Temperature and Pressure Shaped the Evolution of Antifreeze Proteins in Polar and Deep Sea Zoarcoid Fishes" Molecular Biology and Evolution (2025). https://doi.org/10.1093/molbev/msaf219
