title: A Genetic Map for the Only Self-Fertilizing Vertebrate.
abstract: The mangrove killifish Kryptolebias marmoratus, and its close relative Kryptolebias hermaphroditus, are the only vertebrate species known to reproduce by self-fertilization due to functional ovotestis development. To improve our understanding of their genomes, we constructed a genetic map. First, a single F1 fish was made by artificial fertilization between K. marmoratus and K. hermaphroditus strains. F2 progeny were then obtained by self-fertilization of the F1 fish. We used RAD-seq to query genomic DNAs from the two parental strains, the F1 individual and 49 F2 progeny. Results identified 9904 polymorphic RAD-tags (DNA markers) that mapped to 24 linkage groups, corresponding to the haploid chromosome number of these species. The total length of the map was 1248 cM, indicating that about one recombination occurred for each of the 24 homologous chromosome pairs in each meiosis. Markers were not evenly distributed along the chromosomes: in all chromosomes, many markers (> 8% of the total markers for each chromosome) mapped to chromosome tips. Centromeres suppress recombination, and this uneven distribution is probably due to the species' acrocentric chromosomes. Mapped marker sequences were compared to genomic sequences of medaka and platyfish, the next most closely related species with sequenced genomes that are anchored to genetic maps. Results showed that each mangrove killifish chromosome corresponds to a single chromosome of both platyfish and medaka, suggesting strong conservation of chromosomes over 100 million years of evolution. Our genetic map provides a framework for the K. marmoratus/K. hermaphroditus genome sequence and an important resource for understanding the biology of hermaphroditism.
authors: Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan kanamori@bio.nagoya-u.ac.jp sakakura@nagasaki-u.ac.jp.
authors: Akira
authors: A
authors: Kanamori
authors: Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan.
authors: Yosuke
authors: Y
authors: Sugita
authors: Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan.
authors: Yasufumi
authors: Y
authors: Yuasa
authors: Japan Science and Technology Agency (JST) Exploratory Research for Advanced Technology (ERATO) Higashiyama Live-Holonics Project, Nagoya University, Aichi 464-8602, Japan Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi 487-8501, Japan.
authors: Takamasa
authors: T
authors: Suzuki
authors: Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan.
authors: Kouichi
authors: K
authors: Kawamura
authors: Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Aichi 464-8602, Japan.
authors: Yoshinobu
authors: Y
authors: Uno
authors: Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan.
authors: Katsuyasu
authors: K
authors: Kamimura
authors: Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Aichi 464-8602, Japan.
authors: Yoichi
authors: Y
authors: Matsuda
authors: Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403-1254.
authors: Catherine A
authors: CA
authors: Wilson
authors: Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403-1254.
authors: Angel
authors: A
authors: Amores
authors: Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403-1254.
authors: John H
authors: JH
authors: Postlethwait
authors: Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, 852-8521, Japan.
authors: Koushirou
authors: K
authors: Suga
authors: Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, 852-8521, Japan kanamori@bio.nagoya-u.ac.jp sakakura@nagasaki-u.ac.jp.
authors: Yoshitaka
authors: Y
authors: Sakakura
mesh_terms: D000818:Animals; D002503:Centromere; D002874:Chromosome Mapping; D019143:Evolution, Molecular; D056726:Genetic Association Studies; D008040:Genetic Linkage; D016678:Genome; D023281:Genomics; D010802:Phylogeny; D011995:Recombination, Genetic; D057945:Self-Fertilization / Q000235:genetics*; D026801:Synteny; D014714:Vertebrates / Q000145:classification / Q000235:genetics*
keywords: centromeres and recombination; conserved chromosomes; genetics of sex; hermaphrodite; phylogeny by RAD-seq; teleost