Meeting Abstract
Keratin proteins are an important component of the tetrapod integument. Duplication and diversification of keratin genes is associated with the origin of novel integumentary structures like mammalian hair, avian feathers, and scutes covering turtle shells. Accordingly, the loss of integumentary structures can result in loss of keratin genes. For example, many of the hair keratins in dolphins and whales have become pseudogenes. The adhesive setae of geckos and Anolis are composed of both alpha- and beta-keratins and recent whole genome assemblies of a gecko and anole uncovered duplications in seta-specific beta-keratins in each of these lineages. While anoles evolved adhesive toepads just once, geckos have gained and lost adhesive toepads multiple times. The repeated evolution of gecko adhesive toepads suggests two alternative hypothesis: 1) ancient duplications of keratin genes in the most recent common ancestor to geckos that “pre-adapted” geckos to evolve adhesively-competent subdigital setae; or 2) repeated diversification of keratin genes in each lineage with an independently derived functional adhesive system. A further hypothesis asks whether secondarily padless geckos have lost functional keratin genes? I will summarize our current knowledge of keratin gene evolution in geckos and discuss how gecko genome assemblies, combined with phylogenies of keratin genes and gene duplication models, can provide rigorous tests of these hypotheses. This includes a taxon sampling strategy for sequencing and assembly of high quality genomes to investigate the origins and evolution of gecko adhesive toepads.
