Identification of C. reinhardtii bbs1, -4, and -7 mutants. (A) Map showing the genomic region near the BBS4 locus. Black arrows indicate PCR primer pairs; plus and minus signs indicate whether or not these primers gave PCR products. bbs4-1 lacks the entire BBS4 gene. The 6,797-bp fragment used to rescue strain bbs4-1 is indicated. JGI protein IDs of the predicted gene products are shown. (B) Map showing the genomic region near the BBS7 locus. Only one of the tested primer pairs failed to amplify in the ptx6-1 strain. Sequencing of this region revealed the insertion of a retrotransposal footprint into the BBS7 gene of ptx6-1, causing a premature stop after 52 codons. (C) Map showing the genomic region near the BBS1 locus. Approximately half of BBS1 is deleted in bbs1-1. Gene orientation is marked by white arrows. wt, wild type.