“…If the regulatory mechanisms are conserved, the expression pattern would stay the same; if changes happened in cis-regulatory elements or in trans factors, the expression patterns driven by the reporters would vary. For example, in C. elegans, the transcription factor CEH-6 regulates lin-11 expression in the interneuron RIC by binding to an intronic enhancer; in C. briggsae, the endogenous lin-11 enhancer fails to drive expression in RIC, while reciprocal promoter swaps do drive expression in RIC (Amon and Gupta, 2017). Interestingly, an independent comparative RNAi screen found evidence for functional divergence of the CEH-6 transcription factor between C. elegans and C. briggsae (Verster, Ramani, McKay, & Fraser, 2014).…”