Complex trait

Complex traits, also known as polygenic or multigenic traits, are phenotypes determined by the interaction of multiple genetic and environmental factors. A central goal of contemporary genetics research is to understand the molecular mechanisms by which genetic variation influences complex traits. Examples of complex traits in humans include height; intelligence and cognitive function; body-mass index; blood pressure; and risk for complex diseases such as diabetes, heart disease, Alzheimer's disease, and schizophrenia. The genetic architecture of complex traits has been explored using statistical approaches such as genome-wide association studies (GWAS) and quantitative trait loci (QTL) mapping. HistoryWhen Mendel's work on inheritance was rediscovered in 1900, scientists debated whether Mendel's laws could account for the continuous variation observed for many traits. One group known as the biometricians argued that continuous traits such as height were largely heritable, but could not be explained by the inheritance of single Mendelian genetic factors. Work published by Ronald Fisher in 1919 mostly resolved debate by demonstrating that the variation in continuous traits could be