Model selection methods have been successful with disease and trait GWAS studies by using selection techniques to choose multifactorial models that balance the false positive rate, statistical power and computational requirements of the search (Lee et al., 2008; Wray et al., 2007; Wu and Zhao, 2009).
Multifactorial models suggest that the genetic susceptibility due to specific variant alleles in polymorphisms may affect the outcomes of environmental exposure [ 7].
Mann and coworkers have proposed that, given the multifactorial nature of suicidal behavior, a model that would incorporate several, largely independent, predictors would have greater predictive power [ 13].
As AVC is a multifactorial condition, it is essential to develop a simple animal model that may shed more light on this pathophysiological process.
Such findings support the multifactorial model of gastric pathology that includes the host, H. pylori, and the environment [ 13, 36, 39].
This result is consistent with recent genome-wide selection experiments in Eucalyptus showing that a multifactorial model of a few hundred small effects throughout the genome contribute additively to height growth25, in contrast to earlier suggestions of the existence of a relatively small number of loci of larger effect as reported in several biparental QTL mapping studies26.
Commingling analyses indicated that a three-component distribution model best accounts for the variation in age of onset of oesophageal cancer, and that a multifactorial model provides the best fit to the general population data.
The basic premise is that a multifactorial model of disease causation represents a more complex set of beliefs than a single-factor model comprised of only genetic or behavioral causes.
We consider that a multifactorial model – with genetic, epigenetic and environmental influences – provides the best explanation for our observations involving differences of expression of hypodontia and supernumerary teeth in MZ twin pairs (Fig. 1).
Rather than a simple monogenic mode of inheritance alone, we consider that a multifactorial model 7,45,83 – with genetic, epigenetic and environmental influences – provides the best explanation for our observations involving hypodontia and supernumerary teeth in MZ twin pairs, as well as different phenotypic expressions in MZ co-twins with ectodermal dysplasia.
