“…In PDE models on the evolution of gene frequencies, clines are nonconstant equilibrium solutions. The general cline theory of regular migration-selection model can be found in a series of systematic studies by Lou and Nagylaki [8,9,10]; in the review papers by Nagylaki and Lou [17], Lou et al [11], and Bürger [1]; and in recent works by Hofbauer and Su [5,6], Nakashima [22,23,24], Sovrano [26], and Feltrin and Sovrano [2,3].…”