The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related t...The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related traits, body weight （BW） and body length （BL）, were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group （30 per family）. Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various （co）variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively： 0.29 ± 0.01 and 0.22 ± 0.02 at 2 months of age, 0.32 ± 0.02 and 0.30 ± 0.04 at 3 months of age, 0.48 ± 0.04 and 0.40 ± 0.05 at 8 months of age; broad-sense heritability estimates were respectively： 0.44 ± 0.02 and 0.54 ± 0.04 at 2 months of age, 0.35 ± 0.01 and 0.36 ± 0.03 at 3 months of age, 0.49 ± 0.03 and 0.45 ± 0.04. All heritabilities were statistically significant （P 0.05）. Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant （P 0.01）： 0.93 ± 0.02, 0.95 ± 0.03 and 0.92 ± 0.03 respectively. Maternal effect was significant （P 0.05） only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder.展开更多
Genetic expression for an endosperm trait in seeds of cereal crops may be controlled simultaneously by the triploid endosperm genotypes and the diploid maternal genotypes. However, current statistical methods for mapp...Genetic expression for an endosperm trait in seeds of cereal crops may be controlled simultaneously by the triploid endosperm genotypes and the diploid maternal genotypes. However, current statistical methods for mapping quantitative trait loci (QTLs) underlying endosperm traits have not been effective in dealing with the putative maternal genetic effects. Combining the quantitative genetic model for diploid maternal traits with triploid endosperm traits, here we propose a new statistical method for mapping QTLs con- trolling endosperm traits with maternal genetic effects. This method applies the data set of both DNA molecular marker genotypes of each plant in segregation population and the quantitative observations of single endosperms in each plant to map QTL. The maximum likelihood method implemented via the expectation-maximization algorithm was used to the estimate parameters of a putative QTL. Since this method involves the maternal effect that may contribute to en- dosperm traits, it might be more congruent with the genetics of endosperm traits and more helpful to increasing the preci- sion of QTL mapping. The simulation results show the pro- posed method provides accurate estimates of the QTL effects and locations with high statistical power.展开更多
基金Special Fund for Agro-scientific Research in the Public Interest of China under contract No.200903046Research Foundation of Zhejiang Province,China under contract No.2009C12078+1 种基金National Sparking Plan Project of China under contract No.2010GA700010Taishan Scholar Project of Shandong Province,China
文摘The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related traits, body weight （BW） and body length （BL）, were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group （30 per family）. Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various （co）variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively： 0.29 ± 0.01 and 0.22 ± 0.02 at 2 months of age, 0.32 ± 0.02 and 0.30 ± 0.04 at 3 months of age, 0.48 ± 0.04 and 0.40 ± 0.05 at 8 months of age; broad-sense heritability estimates were respectively： 0.44 ± 0.02 and 0.54 ± 0.04 at 2 months of age, 0.35 ± 0.01 and 0.36 ± 0.03 at 3 months of age, 0.49 ± 0.03 and 0.45 ± 0.04. All heritabilities were statistically significant （P 0.05）. Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant （P 0.01）： 0.93 ± 0.02, 0.95 ± 0.03 and 0.92 ± 0.03 respectively. Maternal effect was significant （P 0.05） only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder.
基金supported by the National Natural Science Foundation of China(Grant Nos.39900080,30270724&30370758).
文摘Genetic expression for an endosperm trait in seeds of cereal crops may be controlled simultaneously by the triploid endosperm genotypes and the diploid maternal genotypes. However, current statistical methods for mapping quantitative trait loci (QTLs) underlying endosperm traits have not been effective in dealing with the putative maternal genetic effects. Combining the quantitative genetic model for diploid maternal traits with triploid endosperm traits, here we propose a new statistical method for mapping QTLs con- trolling endosperm traits with maternal genetic effects. This method applies the data set of both DNA molecular marker genotypes of each plant in segregation population and the quantitative observations of single endosperms in each plant to map QTL. The maximum likelihood method implemented via the expectation-maximization algorithm was used to the estimate parameters of a putative QTL. Since this method involves the maternal effect that may contribute to en- dosperm traits, it might be more congruent with the genetics of endosperm traits and more helpful to increasing the preci- sion of QTL mapping. The simulation results show the pro- posed method provides accurate estimates of the QTL effects and locations with high statistical power.
