title: A microsatellite-based genetic linkage map and putative sex-determining genomic regions in Lake Victoria cichlids.
abstract: Cichlid fishes in East Africa have undergone extensive adaptive radiation, which has led to spectacular diversity in their morphology and ecology. To date, genetic linkage maps have been constructed for several tilapias (riverine), Astatotilapia burtoni (Lake Tanganyika), and hybrid lines of Lake Malawi cichlids to facilitate genome-wide comparative analyses. In the present study, we constructed a genetic linkage map of the hybrid line of Lake Victoria cichlids, so that maps of cichlids from all the major areas of East Africa will be available. The genetic linkage map shown here is derived from the F2 progeny of an interspecific cross between Haplochromis chilotes and Haplochromis sauvagei and is based on 184 microsatellite and two single-nucleotide polymorphism (SNP) markers. Most of the microsatellite markers used in the present study were originally designed for other genetic linkage maps, allowing us to directly compare each linkage group (LG) among different cichlid groups. We found 25 LGs, the total length of which was 1133.2cM with an average marker spacing of about 6.09cM. Our subsequent linkage mapping analysis identified two putative sex-determining loci in cichlids. Interestingly, one of these two loci is located on cichlid LG5, on which the female heterogametic ZW locus and several quantitative trait loci (QTLs) related to adaptive evolution have been reported in Lake Malawi cichlids. We also found that V1R1 and V1R2, candidate genes for the fish pheromone receptor, are located very close to the recently detected sex-determining locus on cichlid LG5. The genetic linkage map study presented here may provide a valuable foundation for studying the chromosomal evolution of East African cichlids and the possible role of sex chromosomes in generating their genomic diversity.
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors: Yu
authors: Y
authors: Kudo
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan. Electronic address: mnikaido@bio.titech.ac.jp.
authors: Masato
authors: M
authors: Nikaido
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors: Azusa
authors: A
authors: Kondo
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors: Hikoyu
authors: H
authors: Suzuki
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan; Ecological Genetics Laboratory, National Institute of Genetics, Michima, Shizuoka 411-8540, Japan.
authors: Kohta
authors: K
authors: Yoshida
authors: Fisheries Laboratory, The University of Tokyo, Maisaka, Shizuoka 431-0214, Japan.
authors: Kiyoshi
authors: K
authors: Kikuchi
authors: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan; Foundation for Advancement of International Science, Tsukuba 305-0821, Japan; Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan. Electronic address: nokada@fais.or.jp.
authors: Norihiro
authors: N
authors: Okada
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D023681:Cichlids / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D005819:Genetic Markers; D016678:Genome; D060106:Lakes; D008297:Male; D018895:Microsatellite Repeats; D020641:Polymorphism, Single Nucleotide; D019849:Sex Determination Processes; D013636:Tanzania
chemical_list: D005819:Genetic Markers
keywords: Hybrid line; Linkage group; Linkage mapping