Generation of a nonoverlapping tiling path across the phox2b locus and their expression domains. (a) The zebrafish phox2b interval (chr9: 25101456–25141976; Zv5) was divided into 33 amplicons (total size of 39.3 kb) according to whether intervals could be aligned by MULTIZ to any of four comparator orthologous intervals (fugu, tetraodon, human, or mouse; see Methods). The phox2b exons were excluded. Amplicons are identified based on their distance from the phox2b transcriptional start site and are displayed as custom tracks on the UCSC Genome Browser (genome.ucsc.edu). (b) G0 embryos were raised to sexual maturity, mated with AB fish, and screened for germline transmission of enhancer activity. Expression is noted in the black diamonds below each construct. Black refers to strong expression, gray to weaker expression, and white to no expression. For each positive amplicon at least two G1 founders have been identified that display the reported expression. Those having only one identified founder, thus far, are designated with the *. VDi, ventral diencephalon; LC, locus coeruleus; r, rhombomeres of the hindbrain; CG, cranial ganglia; PA, pharyngeal arches; SC, spinal cord; ENS, enteric nervous system.
