“…It becomes straightforward to define the quantitative trait nucleotides causing this higher order variation among epochs using reduced complexity crosses and coisogenic crosses (Heiker et al, 2014;Kirkpatrick and Bryant, 2014;Kumar et al, 2013;Mulligan et al, 2008). Well-defined epoch effect variants include Gpnmb in vision (Lu et al, 2011(Lu et al, , 2019, Gabra2 in CNS function (Figure 6; (Hawkins et al, 2020;Mulligan et al, 2019), and Taar1 in methamphetamine abuse (Reed et al, 2017;Shi et al, 2016;Stafford et al, 2019).…”