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Quantitative trait locus (QTL) mapping of external egg traits in chickens was carried out with 143 microsatellite markers using 388 F2 hens obtained from an intercross of a Japanese Large Game (Oh-Shamo) male and three White Leghorn females. External egg traits, such as the weight and length of eggs and the weight, thickness, strength, and color of eggshells were measured at three different stages of egg production, i.e. early, middle, and late stages. QTL analyses revealed 10 significant and three suggestive QTLs with main effects on external egg traits on chromosomes 1, 2, 4, 5, 8, 10, 11, 12, 17, and Z. The QTL alleles derived from Oh-Shamo, one of the indigenous Japanese breeds, uniquely increased most external egg traits, whereas some QTL alleles had opposite effects on phenotypic differences between Oh-Shamo and White Leghorn. The QTLs detected accounted for 3.09-15.39% of the phenotypic variances. Although the QTLs on chromosomes 5, 8, and Z were found throughout all three stages, the others were identified at only one or two stages. Epistatic QTLs for external egg traits were not detected in the present study. The age-related changes of our main-effect QTLs illustrate one aspect of the complex genetic basis of external egg traits.

Meat color traits have economic importance and are regulated by multiple genetic loci (quantitative trait loci: QTLs), environmental factors, and their interactions. Using an F2 intercross population between the Oh-Shamo (Japanese Large Game) and White Leghorn chickens, QTL analysis based on the Bayesian model was performed for meat color traits. A total of 280 F2 individuals at 20 weeks of age were genotyped for 88 microsatellite markers covering 21 autosomes. As a result, nine QTLs (two on chromosome 1, two on chromosome 2, and one each on chromosomes 3, 7, 9, 17, and 24) were detected for L* (lightness), a* (redness), and b* (yellowness) values in the breast and thigh muscles. Some QTLs had a single genetic effect only on a meat color trait, however some QTLs exhibited plural genetic effects on the same and/or different traits. For example, the chromosome 3 QTL for the b* value in the raw breast muscle had main, sex-specific, and epistatic-interaction effects on the same trait, and furthermore it had an epistatic effect on a different trait (L* value in the minced thigh muscle). The chromosome 7 QTL had a sex-specific effect on the a* value in raw breast muscle and also had an epistatic effect on a different trait (b* value in the minced thigh muscle). These results clearly indicated that the genetic control of meat color is complex. In addition, this is the first report of QTL mapping focused on the epistatic interaction for meat color traits in chickens.

Quantitative trait locus (QTL) mapping of external egg traits in chickens was carried out with 143 microsatellite markers using 388 F2 hens obtained from an intercross of a Japanese Large Game (Oh-Shamo) male and three White Leghorn females. External egg traits, such as the weight and length of eggs and the weight, thickness, strength, and color of eggshells were measured at three different stages of egg production, i.e. early, middle, and late stages. QTL analyses revealed 10 significant and three suggestive QTLs with main effects on external egg traits on chromosomes 1, 2, 4, 5, 8, 10, 11, 12, 17, and Z. The QTL alleles derived from Oh-Shamo, one of the indigenous Japanese breeds, uniquely increased most external egg traits, whereas some QTL alleles had opposite effects on phenotypic differences between Oh-Shamo and White Leghorn. The QTLs detected accounted for 3.09-15.39% of the phenotypic variances. Although the QTLs on chromosomes 5, 8, and Z were found throughout all three stages, the others were identified at only one or two stages. Epistatic QTLs for external egg traits were not detected in the present study. The age-related changes of our main-effect QTLs illustrate one aspect of the complex genetic basis of external egg traits. [ABSTRACT FROM AUTHOR]

A start-up charge pump circuit for an extremely low input voltage (VIN) is proposed and demonstrated. The proposed circuit uses an inverter level shifter to generate a 2VIN voltage swing to the gate of both main NMOS and PMOS power transistors in a charge pump to reduce the channel resistance. The proposed circuit is fully implemented in a standard 0.18 µm CMOS process, and the measurement result shows that a minimum input voltage of 190 mV is achieved and output power increases by 181% compared with the conventional forward-body-bias scheme at a 300 mV input voltage. The proposed scheme achieves a maximum efficiency of 59.2% when the input voltage is 390 mV and the output current is 320 nA. The proposed circuit is suitable as a start-up circuit in ultralow power energy harvesting power management applications to boost-up from below threshold voltage. [ABSTRACT FROM AUTHOR]