Hints

• Since this is a half-sib analysis, you can leave out the stuff in the example involving sires. Your model will involve only a dam effect and a variance within sibships.

• Include developmental temperature and age as covariates in your analysis. To do this, express the expected number of trunk vertebrae in each individual as

     mu[i] <- nu + beta[dam[i]] + gamma*temp[i] + delta*age[i]
  

  gamma and delta are coefficients that tell you how the expected number of trunk vertebrae depend on developmental temperature and age at measurement, respectively. For example, if gamma $> 0$, then an increase in developmental temperature is associated with an increase in the expected number of trunk vertebrae.

• Use the following priors for your analysis.

    # priors
    nu ~ dnorm(0.0, 0.001)
    gamma ~ dnorm(0.0, 0.001)
    delta ~ dnorm(0.0, 0.001)
    tau.within ~ dgamma(1, 0.25)
    k <- 3*tau.within
    tau.dam ~ dgamma(1, 0.25)I(k,)