This week we'll discuss two conceptual reviews in evolutionary quantitative genetics: Arnold et al. (2001), published in Genetica, and Steppan et al. (2002), published in TREE. Both two take the "Adaptive landscape" as their starting point, and Steppan et al. (2002) do also link the so-called "G-matrix" to the position of the population on the adaptive landscape and how it might affect evolutionary trajectories.
1. What exactly is a G-matrix? What do the diagonal elements mean? What does the off-diagonal elements mean? What can it be used for, and how can one estimate the G-matrix?
2. Are genetic correlations really "constraints" in the sense that they can prevent a population from reaching a fitness optimum (an adaptive peak)? Why? Why not?
3. When do you expect a curved evolutionary trajectory and how is such a curved evolutionary trajectory related to genetic correlations?
4. Is the G-matrix really stable between generations? If not, on what time-scale (-s) can it change and why would it change? What is the role of pleiotropy and physical linkage in the stability of the G-matrix?
5. If two populations have G-matrices that are a/identical, b/proportional or c/unrelated to each other, how can one interpret these patterns?
