Convergence is a fascinating hallmark of evolution that provides comparative biologists with replicated events in the otherwise singular history of life.  Convergent traits that are also experimentally tractable may be termed 'meta-models', allowing biologists to address questions about how repeatable evolution is at different levels of organization.  We propose to bring together a diverse group of collaborators to develop medusozoan cnidarians ("jellyfish") as phylogenetic meta-model to address convergent evolution of eyes as different levels of organization, including genes, cells, and morphology.  This proposal has three primary objectives:

1) To test homology of eyes by generating a data-rich phylogeny that includes new transcriptomes of Medusozoa to reconstruct presence/absence of eyes across the group 2) Compare gene expression profiles of convergently evolved eyes and other tissues (as controls) from cnidarians to identify conserved and convergent patterns, and 3) Incorporate 'tree-thinking' into single-cell transcriptomics to analyze cell-type phylogenies and quantify histories of cell-types in convergently evolved eyes.