A class of latent ancestral graph for modelling the dependence structure of structural vector autoregressive(VAR)model affected by latent variables is proposed.The graphs are mixed graphs with possibly two kind of edg...A class of latent ancestral graph for modelling the dependence structure of structural vector autoregressive(VAR)model affected by latent variables is proposed.The graphs are mixed graphs with possibly two kind of edges,namely directed and bidirected edges.The vertex set denotes random variables at dif-ferent times.In Gaussian case,the latent ancestral graph leads to a simple parameterization model.A modified iterative conditional fitting algorithm is presented to obtain maximum likelihood esti-mation of the parameters.Furthermore,a log-likelihood criterion is used to select the most appropriate models.Simulations are performed using illustrative examples and results are provided to demonstrate the validity of the methods.展开更多
Necessary and sufficient conditions for a maximal ancestral graph(MAnG)to be Markov equivalent to another MAnG and to a DAG are provided respectively.Also a polynomial-time algorithm for converting a MAnG into its equ...Necessary and sufficient conditions for a maximal ancestral graph(MAnG)to be Markov equivalent to another MAnG and to a DAG are provided respectively.Also a polynomial-time algorithm for converting a MAnG into its equivalent DAG is given for the first time.展开更多
Natural variants can significantly improve growth traits in livestock and serve as safe targets for gene editing,thus being applied in animal molecular design breeding.However,such safe and large-effect mutations are ...Natural variants can significantly improve growth traits in livestock and serve as safe targets for gene editing,thus being applied in animal molecular design breeding.However,such safe and large-effect mutations are severely lacking.Using ancestral recombination graphs,we investigated recent selection signatures in beef cattle breeds,pinpointing sweep-driving variants in the LCORL and STC2 loci with notable effects on body size and growth rate.The ACT-to-A frameshift mutation in LCORL occurs mainly in central-European cattle,and stimulates growth.Remarkably,convergent truncating mutations were also found in commercial breeds of sheep,goats,pigs,horses,dogs,rabbits,and chickens.In the STC2 gene,we identified a missense mutation(A60P)located within the conserved region across vertebrates.We validated the two natural mutations in gene-edited mouse models,where both variants in homozygous carriers significantly increase the average weight by 11%.Our findings provide insights into a seemingly recurring gene target of body size enhancing truncating mutations across domesticated species,and offer valuable targets for gene editing-based breeding in animals.展开更多
基金supported in part by the National Natural Science Foundation of China(60375003)the Aeronautics and Astronautics Basal Science Foundation of China(03I53059)
文摘A class of latent ancestral graph for modelling the dependence structure of structural vector autoregressive(VAR)model affected by latent variables is proposed.The graphs are mixed graphs with possibly two kind of edges,namely directed and bidirected edges.The vertex set denotes random variables at dif-ferent times.In Gaussian case,the latent ancestral graph leads to a simple parameterization model.A modified iterative conditional fitting algorithm is presented to obtain maximum likelihood esti-mation of the parameters.Furthermore,a log-likelihood criterion is used to select the most appropriate models.Simulations are performed using illustrative examples and results are provided to demonstrate the validity of the methods.
基金This research was partly supported by the National Natural Science Foundation of China(Grant Nos.39930160&19871003).
文摘Necessary and sufficient conditions for a maximal ancestral graph(MAnG)to be Markov equivalent to another MAnG and to a DAG are provided respectively.Also a polynomial-time algorithm for converting a MAnG into its equivalent DAG is given for the first time.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFF1000100 and 2023YF D1300402)the National Natural Science Foundation of China(Grant No.U21A20120)the Shaanxi Livestock and Poultry Breeding Double-chain Fusion Key Project,China(Grant No.2022GD-TSLD-46-0401).
文摘Natural variants can significantly improve growth traits in livestock and serve as safe targets for gene editing,thus being applied in animal molecular design breeding.However,such safe and large-effect mutations are severely lacking.Using ancestral recombination graphs,we investigated recent selection signatures in beef cattle breeds,pinpointing sweep-driving variants in the LCORL and STC2 loci with notable effects on body size and growth rate.The ACT-to-A frameshift mutation in LCORL occurs mainly in central-European cattle,and stimulates growth.Remarkably,convergent truncating mutations were also found in commercial breeds of sheep,goats,pigs,horses,dogs,rabbits,and chickens.In the STC2 gene,we identified a missense mutation(A60P)located within the conserved region across vertebrates.We validated the two natural mutations in gene-edited mouse models,where both variants in homozygous carriers significantly increase the average weight by 11%.Our findings provide insights into a seemingly recurring gene target of body size enhancing truncating mutations across domesticated species,and offer valuable targets for gene editing-based breeding in animals.
