Takao Namikawa

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Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal(More)
Unlike mammals, avian circadian rhythms are regulated by a multiple oscillatory system consisting of the retina, the pineal and the suprachiasmatic nucleus in the hypothalamus. To understand avian circadian system, we have cloned Clock and Period homologs (qClock, qPer2 and qPer3) and characterized these genes in Japanese quail. Overall, qCLOCK, qPER2 and(More)
A novel satellite DNA sequence of Japanese quail (Coturnix coturnix japonica) was isolated from genomic DNA digested with restriction endonuclease, Bg/II. Sequence analysis of three different-size clones revealed the presence of a tandem array of a GC-rich 41 bp repeated element. This sequence was localized by fluorescence in situ hybridization (FISH)(More)
Using nucleotide sequences of the mitochondrial DNA (mtDNA) cytochrome b and SRY genes, we examined the genetic status of two major groups of domestic cattle, the humpless taurine (Bos taurus) and humped zebu (B. indicus), using 10 cattle populations in Asia. Several sequence polymorphisms specific for each major group were found, although the frequency of(More)
In order to construct a chicken (Gallus gallus) cytogenetic map, we isolated 134 genomic DNA clones as new cytogenetic markers from a chicken cosmid DNA library, and mapped these clones to chicken chromosomes by fluorescence in situ hybridization. Forty-five and 89 out of 134 clones were localized to macrochromosomes and microchromosomes, respectively. The(More)
In the SMXA recombinant inbred (RI) strains, we measured body weight, blood insulin and lipid (triglyceride, total cholesterol and phospholipid) levels in each strain. In the five traits, mean values of substrains varied remarkably and showed a continuous spectrum of distribution, suggesting control by multiple genes at distinct loci for each trait. We also(More)
In birds, females are heterogametic (ZW), while males are homogametic (ZZ). It has been proposed that there is no dosage compensation for the expression of Z-linked genes in birds. In order to examine if the genes are inactivated on one of the two Z chromosomes, we analyzed the allelic expression of the B4GALT1 and CHD-Z genes on Z chromosomes in male(More)
The cytochromeb genes of all living species ofBubalus, including the river type and the swamp type of domestic buffaloes (Bubalus bubalis), were sequenced to clarify their phylogenetic relationships. These sequences were compared together with the African buffalo (Syncerus caffer) and banteng (Bos javanicus) sequences as an outgroup. Phylogenetic trees(More)
The musk shrew (Suncus Murinus) is widely distributed throughout Asia and East Africa. The mitochondrial DNA (mtDNA) of this species was analyzed in individuals from 31 local populations in nine Asian countries and Mauritius, using 17 restriction endonucleases. Although fourteen and nine mtDNA haplotypes were detected from Bangladesh and Nepal,(More)
Cleavage patterns of mitochondrial DNAs (mtDNAs) by 15 restriction endonucleases were analyzed for 10 swamp and 13 river types of domestic water buffaloes. Digestions with nine enzymes exhibited polymorphisms giving two or three kinds of cleavage patterns. Five mtDNA types were identified, three types in the swamp buffaloes of the Philippines, Vietnam, and(More)