Complex traits are traits that are influenced by multiple genes and environmental factors. Examples of complex traits include height, weight, intelligence, and susceptibility to common diseases such as diabetes, heart disease, and cancer.
Polygenic inheritance refers to the inheritance of complex traits that are influenced by the combined effects of multiple genes. Each individual gene has a small effect on the trait, but together, the combined effects of multiple genes can result in a wide range of trait variation in the population. Polygenic inheritance is also influenced by environmental factors, which can further modify the expression of the trait.
Unlike single-gene disorders, complex traits and polygenic inheritance do not follow simple Mendelian inheritance patterns. Instead, the inheritance of these traits can be described by quantitative genetics, which uses statistical methods to measure the contributions of genetic and environmental factors to trait variation.
Quantitative genetics can be used to estimate the heritability of a trait, which is the proportion of variation in the trait that can be attributed to genetic factors. Heritability estimates can help researchers to identify the genetic and environmental factors that contribute to trait variation, and to develop strategies for predicting and managing the risk of complex diseases.
The study of complex traits and polygenic inheritance is an active area of research in genetics and genomics. New tools and technologies, such as genome-wide association studies (GWAS) and polygenic risk scores (PRS), are being developed to better understand the genetic and environmental factors that contribute to complex traits, and to develop personalized strategies for disease prevention and treatment.