SYMPOSIUM The Possibility of De Novo Assembly of the Genome and Population Genomics of the Mangrove Rivulus, Kryptolebias marmoratus

Synopsis How organisms adapt to the range of environments they encounter is a fundamental question in biology. Elucidating the genetic basis of adaptation is a difficult task, especially when the targets of selection are not known. Emerging sequencing technologies and assembly algorithms facilitate the genomic dissection of adaptation and popula-tion differentiation in a vast array of organisms. Here we describe the attributes of Kryptolebias marmoratus, one of two known self-fertilizing hermaphroditic vertebrates that make this fish an attractive genetic system and a model for un-derstanding the genomics of adaptation. Long periods of selfing have resulted in populations composed of many distinct naturally homozygous strains with a variety of identifiable, and apparently heritable, phenotypes. There also is strong population genetic structure across a diverse range of mangrove habitats, making this a tractable system in which to study differentiation both within and among populations. The ability to rear K. marmoratus in the laboratory contributes further to its value as a model for understanding the genetic drivers for adaptation. To date, microsatellite markers distinguish wild isogenic strains but the naturally high homozygosity improves the quality of de novo assembly of the genome and facilitates the identification of genetic variants associated with phenotypes. Gene annotation can be accom-plished with RNA-sequencing data in combination with de novo genome assembly. By combining genomic informatio