Genomic consequences of transitions from cross- to self-fertilization on the efficacy of selection in three independently derived selfing plants

Rob W Ness, Mathieu Siol, Spencer C H Barrett

Transitions from cross- to self-fertilization are associated with increased genetic drift rendering weakly selected mutations effectively neutral. The effect of drift is predicted to reduce selective constraints on amino acid sequences of proteins and relax biased codon usage. We investigated patterns of nucleotide variation to assess the effect of inbreeding on the accumulation of deleterious mutations in three independently evolved selfing plants. Using high-throughput sequencing, we assembled the floral transcriptomes of four individuals of Eichhornia (Pontederiaceae); these included one outcrosser and two independently derived selfers of E. paniculata, and E. paradoxa, a selfing outgroup. The dataset included ~8000 loci totalling ~3.5 Mb of coding DNA.