The Caenorhabditis elegans region surrounding thesex-1 locus (F44A6.2B), and the corresponding region in Caenorhabditis briggsae. The pale blue bar wrapped over two lines represents the region between coordinates 10.18–10.23 Mb ofC. elegans chromosome X, and the navy bar represents 3.50–3.57 Mb of C. briggsae contig RWRA. There are five orthologous briggsae:elegans genes (red) in the conserved segment, which are identified by the same number (1–5) in the two species, and are named on the C. elegans map. Inversion (I) and transposition (T) breakpoints are marked with orange arrows, which are shown arbitrarily on the C. briggsaechromosome. A region including three genes (C07A4.1, F09B9.3, and F09B9.2) has been inverted in either C. elegans or C. briggsae since speciation. Furthermore, a region comprising six genes (gray) between C07A4.1 andF44A6.1 in C. elegans has transposed to another part of the C. briggsae genome, or has transposed into this part of the C. elegans genome.
