Evolution of a system sensitive to stochastic noise: P3.p cell fate in Caenorhabditis

► The frequencies of P3.p cell fates vary among Caenorhabditis species. ► The frequencies of P3.p cell fates vary easily upon random mutation. ► P3.p fate evolution can be mimicked by alterations in Wnt levels. ► The position of the LIN-39/Hox5 level peak varies in Caenorhabditis.