Hello, may I ask is R and S possible to be negative? Thank you! (I am not sure if is bigger number minus the smaller number or follow the formula strictly such that R=average of offspring trait - average of base population trait) thank you ! Hope you could help me (regarding the breeder's equation
They can be measured using specialized methods. It is difficult, however, to account for all. See the interesting problem of "missing heritability": en.wikipedia.org/wiki/Missing_heritability_problem
