RT Journal Article SR Electronic T1 Genetic interaction between two unlinked loci underlies the loss of self-incompatibility in Arabidopsis lyrata JF bioRxiv FD Cold Spring Harbor Laboratory SP 830414 DO 10.1101/830414 A1 Yan Li A1 Mark van Kleunen A1 Marc Stift YR 2019 UL http://biorxiv.org/content/early/2019/11/19/830414.abstract AB As the first step towards the evolution of selfing from obligate outcrossing, identifying the key mutations underlying the loss of self-incompatibility is of particular interest. However, our current knowledge is primarily based on sequence-based comparisons between selfing species and their self-incompatible relatives, which makes it hard to distinguish causal from secondary mutations. To by-pass this problem, we inferred the genetic basis of the loss of self-incompatibility by intercrossing plants from twelve geographically interspersed outcrossing and selfing populations of North-American Arabidopsis lyrata and determining the breeding system of 1,580 progeny. Self-incompatibility was not restored after crosses between different self-compatible populations. Equal frequencies of self-compatible and self-incompatible progeny emerged from crosses between parents with different breeding systems. We propose a two-locus genetic model for the loss of self-incompatibility in which specific S-locus haplotypes (S1 and S19) are associated with loss of self-incompatibility through their interaction with an unlinked modifier.