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Postmating isolation is thought to be an important driver of the late stages of speciation. However, relatively little is empirically known about the process compared with other isolating mechanisms that drive the early stages of speciation, especially in non-model organisms. We characterized the genetic architecture of postmating isolation between 2 rockfishes, Sebastes schlegelii and S. trivittatus , whose reproductive isolation is complete. We examined transmission ratio distortion (TRD) patterns of genetic markers in 2 reciprocal backcross populations. Markers showing either of the 2 types of TRD was widespread across the genome, with some of the distorted markers forming extensive clusters around the recombination coldspots. These suggest that the postmating isolation effectively prevents gene flow across the genome and the recombination landscape contributes to the genetic architecture. Comparisons between 2 backcross families and 2 developmental stages showed little similarity in the distorted markers, suggesting asymmetry and stage specificity of the isolation. This may be due to hybrid incompatibility involving maternal factors or extrinsic selection. The lack of sex-ratio distortion in the mapping families suggested that Haldane's rule in terms of hybrid inviability does not hold. Additionally, quantitative trait loci (QTL) mapping detected significant QTLs for sex and the morphological traits relevant to speciation and convergence of rockfishes, including body coloration. Genes in the melanocortin system, including agouti-signaling protein 1 (asip1) and melanocortin 1 receptor (mc1r), might underlie the horizontal and vertical color patterns on the body, respectively. These findings constitute an essential step toward a comprehensive understanding of speciation and morphological diversification of rockfishes. [ABSTRACT FROM AUTHOR]

A digital phase meter (DPM) for power frequencies with a very low measurement uncertainty of 1 μrad was developed at Japan Electric Meters Inspection Corporation (JEMIC) to establish a power and energy calibration system. We also developed a phase meter calibrator (PMC) for calibrating the DPM. Since the DPM and PMC are synchronized with a single clock, the DPM can be calibrated by a very simple measurement method, which no longer requires extra standards. The DPM has been employed as an instrument for the primary standard of power and energy in Japan to achieve precise phase angle measurement. Since the error in the power measurement at power factor 0 is equal to the error in the phase angle measurement, we verified the performance of the DPM by calibrating a standard power meter using the power calibrators at JEMIC and Physikalische-Technische Bundesanstalt (PTB), and comparing the test results at power factor 0. According to the measurement, the phase angle difference between JEMIC and PTB is within 7 μrad. [ABSTRACT FROM AUTHOR]