Genetic Architecture of the Variation in Male-Specific Ossified Processes on the Anal Fins of Japanese Medaka.
Traits involved in reproduction evolve rapidly and show great diversity among closely related species. However, the genetic mechanisms that underlie the diversification of courtship traits are mostly unknown. Japanese medaka fishes (Oryzias latipes) use anal fins to attract females and to grasp females during courtship; the males have longer anal fins with male-specific ossified papillary processes on the fin rays. However, anal fin morphology varies between populations: the southern populations tend to have longer anal fins and more processes than the northern populations. In the present study, we conducted quantitative trait locus (QTL) mapping to investigate the genetic architecture underlying the variation in the number of papillary processes of Japanese medaka fish and compared the QTL with previously identified QTL controlling anal fin length. First, we found that only a few QTL were shared between anal fin length and papillary process number. Second, we found that the numbers of papillary processes on different fin rays often were controlled by different QTL. Finally, we produced another independent cross and found that some QTL were repeatable between the two crosses, whereas others were specific to only one cross. These results suggest that variation in the number of papillary processes is polygenic and controlled by QTL that are distinct from those controlling anal fin length. Thus, different courtship traits in Japanese medaka share a small number of QTL and have the potential for independent evolution.
Division of Ecological Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Maiko
M
Kawajiri
Tropical Biosphere Research Center and Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
Shingo
S
Fujimoto
Division of Ecological Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Kohta
K
Yoshida
Tropical Biosphere Research Center and Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
Kazunori
K
Yamahira
Division of Ecological Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan School of Life Sciences, SOKENDAI, Mishima, Shizuoka 411-8540, Japan jkitano@lab.nig.ac.jp.
Jun
J
Kitano
D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D056726:Genetic Association Studies; D014644:Genetic Variation; D005838:Genotype; D008126:Lod Score; D008297:Male; D009990:Oryzias / Q000235:genetics*; D010012:Osteogenesis / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D012737:Sex Factors
courtship; genetic correlation; medaka; median fin; ornament