This talk is about statistical genetics, an interdisciplinary topic between statistical physics and population biology. The focus is on the phase of quasi-linkage equilibrium (QLE). Our goals here are to clarify under which conditions the QLE phase can be expected to hold in population biology and how the stability of the QLE phase is lost. The QLE state, which has many similarities to a thermal equilibrium state in statistical mechanics, was discovered by M Kimura for a two-locus two-allele model, and was extended and generalized to the global genome scale by Neher & Shraiman (2011). What we will refer to as the Kimura–Neher–Shraiman theory describes a population evolving due to the mutations, recombination, natural selection and possibly genetic drift. A QLE phase exists at sufficiently high recombination rate (r) and/or mutation rates μ with respect to selection strength. We show how in QLE it is possible to infer the epistatic parameters of the fitness function from the knowledge of the (dynamical) distribution of genotypes in a population. We further consider the breakdown of the QLE regime for high enough selection strength. We review recent results for the selection-mutation and selection-recombination dynamics. Finally, we identify and characterize a new phase which we call the non-random coexistence where variability persists in the population without either fixating or disappearing.

报告人简介：

Erik Aurell 教授是瑞典皇家工学院教授，他在非线性科学、随机组合优化、非平衡统计物理、生物信息学等诸多课题都发表过有重要国际影响的学术论文，是国际统计物理学界知名学者。近年来 Aurell 教授发展了一种研究统计物理反问题的计算方法和理论，并将它成功用于基因序列共演化的研究中，取得了很有意义的成果。

邀请人：周海军 研究员