Fig. 2. Positional cloning of the gene clk-2. (A) clk-2 is inseparable from lin-39 by genetic mapping. (B) Cosmids in bold rescue clk-2(qm37). (C) Fragments and subclones of C07H6; rescuing clones are in bold. Coordinates refer to bases on C07H6. (D) Genomic structure of clk-2 and cux-7, which is the upstream gene in the operon of clk-2. cDNA clone yk215f6 does not contain the entire 3' end of cux-7, stopping at 35040; we use the in-frame stop codon, at 34999, as the 3' end in the drawing. (Accession Numbers: clk-2, AF400665; cux-7, AF400666.) The qm37 mutation is indicated.