A polygene, multiple factor, multiple gene inheritance, or quantitative gene is a group of non-epistatic genes that together influence a phenotypic trait. The precise loci or identities of the non-allelic genes are often unknown to biologists. Advances in statistical methodology and high throughout sequencing are, however, allowing researchers to locate candidate genes for the trait. These genes are generally pleiotropic as well. The genes that contribute to type 2 diabetes are thought to be mostly polygenes.