- E. Xing, S. H. Song, E. Silver. 2015. 10-708 : Probabilistic Graphical Models , Spring 2015 27 : Case study with popular GM III. Abstract: We would like to know what genetic variations cause diseases. The naive view of this process is that one genetic variation (e.g. a Single Nucleotide Polymorphism (SNP), or copy number variation, etc.) causes one disease. However, most disease processes are much more complex. For example, flu susceptibility is influenced by many genes (as well as the environment). Furthermore, many diseases are not truly binary variables – they may consist of a cluster of traits (e.g. coronary heart disease) or occur on a gradient (e.g. there’s no sharp cutoff for how much insulin resistance counts as Type II diabetes). The biological phenomenon of one gene causing multiple traits is known as “pleiotropy”. Multiple genes influencing a single trait, such that one gean may mask the effect of another, is known as “epistasis”.
