Genetic, Comparative Genomic, and Expression Analyses of the Mc1r Locus in the Polychromatic Midas Cichlid Fish (Teleostei, Cichlidae Amphilophus sp.) Species Group

作     者：Henning, Frederico Renz, Adina Josepha Fukamachi, Shoji Meyer, Axel 

作者机构：Univ Konstanz Lehrstuhl Zool & Evolut Biol Fachbereich Biol D-78457 Constance Germany 

出 版 物：《JOURNAL OF MOLECULAR EVOLUTION》 (分子演化杂志)

年 卷 期：2010年第70卷第5期

页      面：405-412页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 09[农学] 071007[理学-遗传学] 0901[农学-作物学] 090102[农学-作物遗传育种] 

基　　金：DFG (Deutsche Forschungsgemeinschaft) International Human Frontier Science Program Organization [00059/2005-L] CNPq (Brazilian National Counsel of Scientific and Technologic Development)/DAAD (Deutscher Akademischer Austausch Dienst) 

主　　题：Conserved non-coding elements CNEs Comparative genomics Fish body coloration Melanocortin-1 receptor Bacterial artificial chromosome 

摘      要：Natural populations of the Midas cichlid species in several different crater lakes in Nicaragua exhibit a conspicuous color polymorphism. Most individuals are dark and the remaining have a gold coloration. The color morphs mate assortatively and sympatric population differentiation has been shown based on neutral molecular data. We investigated the color polymorphism using segregation analysis and a candidate gene approach. The segregation patterns observed in a mapping cross between a gold and a dark individual were consistent with a single dominant gene as a cause of the gold phenotype. This suggests that a simple genetic architecture underlies some of the speciation events in the Midas cichlids. We compared the expression levels of several candidate color genes Mc1r, Ednrb1, Slc45a2, and Tfap1a between the color morphs. Mc1r was found to be up regulated in the gold morph. Given its widespread association in color evolution and role on melanin synthesis, the Mc1r locus was further investigated using sequences derived from a genomic library. Comparative analysis revealed conserved synteny in relation to the majority of teleosts and highlighted several previously unidentified conserved non-coding elements (CNEs) in the upstream and downstream regions in the vicinity of Mc1r. The identification of the CNEs regions allowed the comparison of sequences from gold and dark specimens of natural populations. No polymorphisms were found between in the population sample and Mc1r showed no linkage to the gold phenotype in the mapping cross, demonstrating that it is not causally related to the color polymorphism in the Midas cichlid.