Convergent genomic basis of lip trophic novelties in cichlid fishes

Cichlid fishes have repeatedly evolved an astounding diversity of trophic morphologies. For example, hypertrophied lips have evolved multiple times in both African and Neotropical cichlids. Hypertrophied lips could have even evolved convergently several times within single species assemblages such as the one found in Lake Malawi in Africa. However, the extremely high diversification rate in Lake Malawi cichlids coupled with the extensive potential for hybridization has cast doubt on whether even genome level molecular phylogenetic reconstructions could delineate if these types of adaptations have evolved once or multiple times repeatedly. To examine the genomic basis of this iconic trait using genome wide association, we analyzed the genomes of 39 Lake Malawi cichlids, including 15 de novo resequenced genomes. Tests for introgression indicate there is not widespread introgression between the hypertrophied lip lineages and taken together suggest this classic trophic phenotype has likely evolved at least twice independently within Lake Malawi. Cichlid fishes have long been known for their many examples of convergent phenotypes, but they are rapidly becoming iconic examples of convergent genomic evolution.