Compared with univariate models, multivariate models can be more powerful in cases where multiple traits are influenced by a common genetic variant.
In 1918 British statistician and geneticist Ronald Aylmer Fisher published a paper that showed how Gregor Mendel's laws of inheritance applied to complex traits influenced by multiple genes and environmental factors.
For body size and fecundity, we found a more complex pattern with additive and dominant QTLs explaining about 40% of total phenotypic variance, and both traits influenced by multiple QTLs scattered throughout the genome.
Without regression modelling with a spline function, some of our findings could have been overlooked, in particular, those that demonstrate that multiple personality traits influence adherence behaviour independently, especially in individuals who score very highly on Conscientiousness and Agreeableness.
The same weave of personality traits influences Mr. Thomas's songwriting.
Such traits influence social relationships and adaptation [25, 26, 33].
And just like traits influence action, actions can also influence traits.
Genetic correlations among migration-related traits within this experimental population could result either from close linkage among genes associated with these traits or from the pleiotropic actions of the same genes influencing multiple traits.
This can occur if the same genes influence multiple traits, if genes for different traits are closely linked on chromosomes, or if environmental effects (e.g., temperature or diet) simultaneously influence multiple traits.
The associations identified so far represent only a fraction of those that influence phenotype, because there are likely to be many variants across the entire frequency spectrum, each of which influences multiple traits, with only a small average contribution to the phenotypic variance.
