Map-based cloning of the LjRHL1 locus. A, A schematic of L. japonicus chromosome VI. B, Two overlapping transformation-competent artificial chromosome clones, TM1904 and BM2019, with genetic markers linked to the LjRHL1 locus are indicated. Number of recombinants versus total number of homozygous mutant individuals tested for a given marker is shown in parentheses. C, The region delimited by BK003 and BK001 genetic markers was predicted to contain four genes encoding a presumed zinc finger protein (ZFP), an alcohol dehydrogenase (ADH), unknown protein (UP), and a bHLH domain-containing protein (bHLH). D, Exon-intron structure of the LjRHL1 gene. The positions of genetic lesions in Ljrhl1-1 and Ljrhl1-2 mutant alleles are indicated.