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G3 (Bethesda). 2016 Apr 7;6(4):1095-106. doi: 10.1534/g3.115.022699.

A Genetic Map for the Only Self-Fertilizing Vertebrate.

Author information

1
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.
2
Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan.
3
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.
4
Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan.
5
Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Aichi 464-8602, Japan.
6
Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403-1254.
7
Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, 852-8521, Japan.
8
Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, 852-8521, Japan kanamori@bio.nagoya-u.ac.jp sakakura@nagasaki-u.ac.jp.

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.

KEYWORDS:

centromeres and recombination; conserved chromosomes; genetics of sex; hermaphrodite; phylogeny by RAD-seq; teleost

PMID:
26865699
PMCID:
PMC4825644
DOI:
10.1534/g3.115.022699
[Indexed for MEDLINE]
Free PMC Article

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