ABSTRACT

The biodiversity of vertebrate animals includes 30,000 land vertebrates (tetrapods, including humans) as well as >30,000 species of modern fishes (teleosts). It remains challenging to compare the two groups directly because they significantly changed from their common ancestor 450 million years ago: tetrapod bodies underwent major transitions when they emerged from fishes and began to live on land; teleosts drastically changed their genome organization and gained thousands of extra genes. This NSF EDGE project develops the archaic and uniquely informative garfishes (Lepisosteidae) as research organisms that bridge the disparate worlds of tetrapods and teleosts. Their genome resembles the tetrapod genome in its organization while gars develop very similar to teleosts, making gars a ?Rosetta Stone? to understand vertebrate evolution and our own biological origins. The project will improve gar husbandry and spawning techniques and develop novel methodologies for genetic manipulations such as CRISPR genome editing to test gar gene functions. This will make gars available as experimental species for comparative genomic, evolutionary, developmental, physiological, behavioral, regeneration, and ecological research among the broad community of vertebrate biologists. The project will train the next generation of vertebrate biologists through laboratory experiences for K-12 and undergraduate students, gar conferences, and workshops on vertebrate evolutionary genetics. Public seminars, animal donations to aquaria and zoos, and strong social media presence will strengthen scientific literacy of the general public by emphasizing the importance of fishes for understanding evolution, genetics, and development. Thereby, the project will raise awareness for the ecological significance of declining gar populations.

The evolution of vertebrates has been accompanied by lineage-specific gains and losses of genes and morphological structures. Research organisms with informative genomes, development, and phenotypic traits are thus essential to understand vertebrate origins, major transitions, their biodiversity, and genome functions. This project will enable the investigation of broad biological questions across vertebrate evolution by developing genome-to-phenome technologies for the spotted gar (Lepisosteus oculatus) that occupies a key phylogenetic position among bony vertebrates. Gars serve both as an experimentally accessible, "unduplicated" outgroup to the teleost fishes that went through a whole genome duplication event early in their evolution as well as an outgroup to lobe-finned vertebrates including tetrapods. The gar genome assembly has been used in 300+ genomic studies, but functional genetic investigations that enable direct testing of genotype-to-phenotype relations in gar are currently lacking. This project leverages ongoing research efforts in order to facilitate the genome enablement of gar. Resources and genetic tools to be developed include: 1.) improvements in gar spawning techniques and infrastructure to perform molecular genetic experiments in gar; 2.) advances in CRISPR genome editing, targeted gene silencing, and transgenic technologies for the gar model; and 3.) dissemination of project results through a project-specific online database, two Gar Conferences, and two Workshops on Functional Vertebrate Evo-Devo Genomics. The project thereby seeks to understand the role of a select set of gar genes and regulatory elements as proof-of-principle to unlock the full potential of gars as model organisms for broad research questions in comparative vertebrate biology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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