A Genetic Map for the Only Self-Fertilizing Vertebrate. Kryptolebias marmoratus

The mangrove killifish, Kryptolebias marmoratus, and its close relative Kryptolebias hermaphroditus, are the only vertebrate species known to reproduce by self-fertilization. To make a genetic map of these species, we generated an F1 by artificial fertilization between two strains, the K. hermaphroditus strain PAN-RS and the K. marmoratus strain DAN. We RAD-sequenced the parental strains, the F1, and 49 F2 progeny obtained from self-fertilization of an F1 fish. From about 10,000 polymorphic RAD-tags (100 nucleotide-long DNA markers adjacent to SbfI cut sites) we obtained a genetic map with 24 linkage groups, which corresponds to the known haploid chromosome number for these Kryptolebias species. This genetic map provides a genomic tool for 1) assembly of genome sequences obtained from next-generation sequencing, 2) positional cloning of candidate genes from mutagenesis screening, and 3) mapping of various QTL loci from wild fish or recombinant inbred lines, which can be obtained easily due to self-fertilization, and an important resource for understanding the biology of hermaphroditism.