2011/08/08 by Richard A. Neher, Boris I. Shraiman · 1 citation
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #q-bio.PE #cond-mat.stat-mech #physics.bio-ph
paper · pdf · doi:10.1103/revmodphys.83.1283
published as Rev. Mod. Phys. 83, 1283-1300 (2011) · to appear in Rev.Mod.Phys
arxiv created 2011/08/08 · arxiv updated 2012/08/01
The distribution and heritability of many traits depends on numerous loci in the genome. In general, the astronomical number of possible genotypes makes the system with large numbers of loci difficult to describe. Multilocus evolution, however, greatly simplifies in the limit of weak selection and frequent recombination. In this limit, populations rapidly reach Quasi-Linkage Equilibrium (QLE) in which the dynamics of the full genotype distribution, including correlations between alleles at different loci, can be parameterized by the allele frequencies. This review provides a simplified exposition of the concept and mathematics of QLE which is central to the statistical description of genotypes in sexual populations. We show how key results of Quantitative Genetics such as the generalized Fisher's "Fundamental Theorem", along with Wright's Adaptive Landscape, emerge within QLE from the dynamics of the genotype distribution. We then discuss under what circumstances QLE is applicable, and what the breakdown of QLE implies for the population structure and the dynamics of selection. Understanding of the fundamental aspects of multilocus evolution obtained through simplified models may be helpful in providing conceptual and computational tools to address the challenges arising in the studies of complex quantitative phenotypes of practical interest.