Many features are conserved between the mammalian nephron and planarian protonephridia.

(A) Image of a young adult C. elegans and schematic depicting the twelve pairs of sensory neurons in the anterior amphid individuals carrying a virus with k deleterious mutations at its endemic equilibrium. class carrying the fewest number of deleterious mutations is defined as mutation class k = 0. Inset: variation in the basic reproductive rate of infected individuals (gray histogram) and variation in the net reproductive rate R of infected individuals (brown histogram) resulting from variation in the number of deleterious mutations carried by circulating viruses.

Listed are, for each triplet of cell types, the probabilities of the four topologies for prior odds p(βi=1)p(βi=0)=0.05; the number of topologies that reach probability p(T | {giA,B,C})>0.6 for some value of p(βi=1)p(βi=0) between 10−6 and 102; the non-null topology that has the highest probability p(T | {giA,B,C}) over the range of prior odds (if the null topology is the most likely topology for the entire range of prior odds, the topology is marked ‘null’); and the value of highest probability p(T | {giA,B,C}) over the range of prior odds; the correct topology and triplet length in the traditional model; and the correct topology and triplet length in the Adolfsson model.

(A) Doxycycline-inducible gam-gfp fusion construct in the E. coli chromosome. Constitutively produced TetR protein represses the PN25tetO promoter, which produces GamGFP upon doxycycline induction. oriC, origin of replication; ter, replication terminus; arrows, directions of transcription. (B) Phage λ assay for end-blocking activity by Mu Gam and GamGFP. Rolling-circle replication of phage λred gam is inhibited by E. coli RecBCD, which causes small plaques of λred gam on wild-type E. coli (Smith, 1983). Mu Gam protein binds and protects DNA ends from RecBCD exonuclease activity (Akroyd and Symonds, 1986) and so is expected to allow rolling-circle replication of λred gam and therefore allow formation of large plaques. (C) λred gam plaques are small on recB+ (WT) and large on recB-deficient cells (recB-). Plaques produced on WT cells carrying gam and gam-gfp are small when Gam and GamGFP proteins are not produced (Uninduced). (D) λred gam produce large plaques on WT cells if Gam or GamGFP are produced (Induced). (E) UV sensitivity of E. coli recB-null mutant compared with recB+(WT), and uninduced gam and gam-gfp carrying cells. WT (), recB (), WT GamGFP, (); WT Gam, (). (F) Induction of Gam or GamGFP with 200 ng/ml doxycycline causes UV sensitivity similar to that of recB-null mutant cells, indicating that Gam or GamGFP block RecBCD action on double-stranded DNA ends. WT, SMR14327; recB, SMR8350; WT GamGFP, SMR14334; WT Gam, SMR14333. Representative experiment performed three times with comparable results.