With biological and economic importance,threshold traits are discrete in phenotype but have the same polygenic genetic basis as quantitative traits. The traditional linkage analysis for quantitative traits is invalid ...With biological and economic importance,threshold traits are discrete in phenotype but have the same polygenic genetic basis as quantitative traits. The traditional linkage analysis for quantitative traits is invalid for threshold traits due to their special characters. The transmission disequilibrium test (TDT) has received great attention recently in localizing human disease genes due to its simplicity and powerfulness. But TDT only deals with data from independent nuclear families and it will lose information about extended pedigree that incorporates information not only from parents and siblings but also from other relatives. The pedigree disequilibrium test (PDT) proposed by Martin in 2001 can be used to analyze the extended pedigree in human.In this study, PDT was introduced into the QTL mapping of threshold traits for farm animals, and was modified in order to accommodate the pedigree structures of farm animals.The modified PDT was renamed pedigree transmission disequilibrium test (PTDT) and its power and type I error were investigated and compared with that of PDT by Monte Carlo simulation. It was shown that PTDT is a robust and valid approach to mapping QTL of threshold trait. When the parental information is complete, PTDT and PDT are almost the same in terms of power and type I error. However, if the parental information is missing to a certain extent, PTDT is higher in power and lower in type I error than PDT. These results imply that PTDT can be a novel approach to QTL fine mapping of threshold traits based on the existing coarse mapping information.展开更多
Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black sp...Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black spruce （Picea mariana） and jack pine （Pinus banksiana） seedlings were exposed to 5, 10, 15, 20, 25, 30 and 35℃ soil temperature in greenhouses. After 90 days of the treatment, net photosynthetic rate （A）, stomatal conductance （gs）, transpiration rate （E）, water use efficiency （WUE） and specific leaf area （SLA） were measured. This study showed that all the traits had an asymmetrical peak relationship with changing soil temperature, the relationship was well simulated using a cubic curvilinear model, and the exact thresholds could be derived from the second derivative of the model. The results revealed that the thresholds varied among ecophysiological traits and between tree species. In black spruce, the thresholds were 14.1, 14.7, 10.7, 14.4 and 16.2℃ forA, gs, E, WUE and SLA; 15.4, 10.4, 14.7, 16.9 and 10.5℃ for the corresponding traits in jack pine. The lowest thresholds of E in black spruce and gs in jack pine were an indicator representing the minimum requirement of soil temperature for the regular processes of ecophysiology. The highest thresholds of SLA in black spruce and WUE in jack pine suggest they are the most sensitive to decreasing soil temperature and may play an important role in the acclimation. The averaged thresholds were at 14.0 and 13.6℃ for black spruce and jack pine, suggesting that the sensitivity of both species to low soil temperature was quite close.展开更多
目的:探讨大学生阈下自闭特质、孤独感和社交媒体错失恐惧的关系,以及孤独感在两者间的中介作用。方法:采用自闭谱系商数问卷(Autism-spectrum Quotient,AQ)、UCLA孤独量表、错失恐惧量表(Fear of Missing Out Scale,FOMOS)对783名大学...目的:探讨大学生阈下自闭特质、孤独感和社交媒体错失恐惧的关系,以及孤独感在两者间的中介作用。方法:采用自闭谱系商数问卷(Autism-spectrum Quotient,AQ)、UCLA孤独量表、错失恐惧量表(Fear of Missing Out Scale,FOMOS)对783名大学生进行调查研究。结果:(1)阈下自闭特质与社交媒体错失恐惧呈显著正相关(r=0.13,P<0.01),阈下自闭特质与孤独感呈显著正相关(r=0.31,P<0.01),社交媒体错失恐惧与孤独感呈显著正相关(r=0.21,P<0.01);(2)阈下自闭特质不仅对社交媒体错失恐惧有直接正向预测作用(β=0.13,P<0.01),还能通过孤独感间接影响社交媒体错失恐惧。结论:孤独感在阈下自闭特质与社交媒体错失恐惧间起中介作用。展开更多
文摘With biological and economic importance,threshold traits are discrete in phenotype but have the same polygenic genetic basis as quantitative traits. The traditional linkage analysis for quantitative traits is invalid for threshold traits due to their special characters. The transmission disequilibrium test (TDT) has received great attention recently in localizing human disease genes due to its simplicity and powerfulness. But TDT only deals with data from independent nuclear families and it will lose information about extended pedigree that incorporates information not only from parents and siblings but also from other relatives. The pedigree disequilibrium test (PDT) proposed by Martin in 2001 can be used to analyze the extended pedigree in human.In this study, PDT was introduced into the QTL mapping of threshold traits for farm animals, and was modified in order to accommodate the pedigree structures of farm animals.The modified PDT was renamed pedigree transmission disequilibrium test (PTDT) and its power and type I error were investigated and compared with that of PDT by Monte Carlo simulation. It was shown that PTDT is a robust and valid approach to mapping QTL of threshold trait. When the parental information is complete, PTDT and PDT are almost the same in terms of power and type I error. However, if the parental information is missing to a certain extent, PTDT is higher in power and lower in type I error than PDT. These results imply that PTDT can be a novel approach to QTL fine mapping of threshold traits based on the existing coarse mapping information.
基金supported by the Lakehead University Graduate Fellowship, Nature Science and Engineer Research Council Scholarship of Canada (NSERC) PGS A,the National Natural Science Foundation of China (Grant No. 30872000)K. C. Wong Education Foundation of Hong Kong (2008) and the funding initiative of Institute of Mountain Hazards and Environment, Chinese Academy of Sciences to the author and NSERC research grant to Qing-Lai Dang
文摘Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysi-ological traits of trees, but difficultly determined the exact values. To resolve the problem, black spruce （Picea mariana） and jack pine （Pinus banksiana） seedlings were exposed to 5, 10, 15, 20, 25, 30 and 35℃ soil temperature in greenhouses. After 90 days of the treatment, net photosynthetic rate （A）, stomatal conductance （gs）, transpiration rate （E）, water use efficiency （WUE） and specific leaf area （SLA） were measured. This study showed that all the traits had an asymmetrical peak relationship with changing soil temperature, the relationship was well simulated using a cubic curvilinear model, and the exact thresholds could be derived from the second derivative of the model. The results revealed that the thresholds varied among ecophysiological traits and between tree species. In black spruce, the thresholds were 14.1, 14.7, 10.7, 14.4 and 16.2℃ forA, gs, E, WUE and SLA; 15.4, 10.4, 14.7, 16.9 and 10.5℃ for the corresponding traits in jack pine. The lowest thresholds of E in black spruce and gs in jack pine were an indicator representing the minimum requirement of soil temperature for the regular processes of ecophysiology. The highest thresholds of SLA in black spruce and WUE in jack pine suggest they are the most sensitive to decreasing soil temperature and may play an important role in the acclimation. The averaged thresholds were at 14.0 and 13.6℃ for black spruce and jack pine, suggesting that the sensitivity of both species to low soil temperature was quite close.
文摘目的:探讨大学生阈下自闭特质、孤独感和社交媒体错失恐惧的关系,以及孤独感在两者间的中介作用。方法:采用自闭谱系商数问卷(Autism-spectrum Quotient,AQ)、UCLA孤独量表、错失恐惧量表(Fear of Missing Out Scale,FOMOS)对783名大学生进行调查研究。结果:(1)阈下自闭特质与社交媒体错失恐惧呈显著正相关(r=0.13,P<0.01),阈下自闭特质与孤独感呈显著正相关(r=0.31,P<0.01),社交媒体错失恐惧与孤独感呈显著正相关(r=0.21,P<0.01);(2)阈下自闭特质不仅对社交媒体错失恐惧有直接正向预测作用(β=0.13,P<0.01),还能通过孤独感间接影响社交媒体错失恐惧。结论:孤独感在阈下自闭特质与社交媒体错失恐惧间起中介作用。
