[R-sig-ME] MCMCglmm prior specification

[Iker Vaquero Alba]

   Hello everyone,
   I am reading a lot of documentation at the moment about prior specification in MCMCglmm, and there is still something I have not very clear. According to some sources, there are mainly two elements to take into account when defining a prior:   - An R structure that needs to be specified for each fixed effect. And
   - A G structure for each random effect.
   However, in other sources another element, B, is introduced as well, which refers to fixed effects too. In Jarrod's Course Notes, I see that both R and B have to do with fixed effects: R specifies V and nu arguments for the variance, and B specifies V and mu elements for the mean.
   
   My confusion comes from the fact that almost every time I see an example of a prior, it just has two elements, R (for fixed effects) and G (for random effects). Why is this? Is it not so important to define a prior for the mean? Is it enough with a prior specification for the variance of fixed effects and another one for all the random effects?
   Thank you very much in advance.   Iker

  
__________________________________________________________________

   Iker Vaquero-Alba
   Visiting Postdoctoral Research Associate
   Laboratory of Evolutionary Ecology of Adaptations 
   Joseph Banks Laboratories
   School of Life Sciences
   University of Lincoln   Brayford Campus, Lincoln
   LN6 7DL
   United Kingdom

   https://eric.exeter.ac.uk/repository/handle/10036/3381


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