Quantitative Genetics

Abstract

Quantitative genetics is one of the disciplines of genetics dealing with the mechanism of quantitatively inherited traits. Classical quantitative genetics is also called statistical genetics or biometrical genetics, as the study of this discipline was basically to use statistical analysis for detecting possible genetic models for designed genetic populations. Fisher established the additive-dominance genetic model based on multiple-factor Mendelian inheritance for quantitative traits to separate the gene effect and the genetic variance into the additive and dominance parts in 1918. His simple genetic model was extended into those with various epistases and a series of procedures to detect and verify the genetic model and related genetic effects were established in 1940s–1960s. Since the effects of individual genes in the genetic system may differ from each other, large or small, the concept and analytical procedure of a single major gene plus polygene mixed inheritance model was raised and then the hypothesis of generalized major gene plus polygene mixed inheritance model along with the corresponding segregation analysis procedures were established during 1970s–1990s. With molecular markers, the QTL mapping was developed and has made the study of quantitative inheritance much easier and broader. The development of molecular quantitative genetics has provided a way of genetic dissection of a quantitative trait. With the progress made in analytical and statistical techniques now allows the construction of regulatory networks that integrate the different levels of the biological information flow from gene-to-function, the hypothesis of gene network of quantitative inheritance might be demonstrated with future experimental practices.