National evaluations often use linear models for normally distributed traits or nonlinear models for traits with non-normal distributions, but international evaluations are usually restricted to linear models for simpler computing.
The relationship between longevity and type traits was most often nonlinear, in particular for udder traits, but in this study, no trait with a clear intermediate optimum was found.
However, univariate analyses of complex traits like cuticular hydrocarbon blends can significantly underestimate nonlinear selection operating in multivariate trait space [ 32].
Our methodology combines previous quantitative genetic models of disease traits with nonlinear stochastic modeling of the individual-level infection process.
In addition, genes producing products that affect traits undergoing nonlinear selection, specifically with concave fitness functions around the optimum, are more likely to be lost early.
Linear model equations for genomic selection were first developed by Nejati-Javaremi et al. [ 8] and are nearly as accurate as nonlinear equations for most traits [ 1].
Accordingly, predation reduced the variance of TL, which resulted in negative nonlinear selection differentials of this trait.
This study suggests that QTL mapping using a nonlinear approach and considering multiple traits may improve the mapping precision.
It is a common belief in genomics that nonlinear interactions (epistasis) in complex traits make the task of reconstructing genetic models extremely difficult, if not impossible.
I found no evidence of nonlinear selection acting on this plant trait in the four populations (Additional file 2).
