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Genetic variation for pseudo‐self‐compatibility in self‐incompatible populations of Leavenworthia alabamica (Brassicaceae)
Author(s) -
Baldwin Sarah J.,
Schoen Daniel J.
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14109
Subject(s) - biology , allele , genetics , heritability , genetic variation , outcrossing , locus (genetics) , population , brassicaceae , pollen , botany , gene , demography , sociology
Summary Self‐incompatibility ( SI ) promotes outcrossing, but transitions to self‐compatibility ( SC ) are frequent. Population genetic theory describing the breakdown of SI to SC suggests that, under most conditions, populations should be composed of either SI or SC individuals. Under a narrow range of conditions, theory suggests that SI may persist alongside reduced expression of SI (pseudo‐ SI , PSI ) in mixed‐mating populations. We studied genetic variation for PSI segregating in four SI populations of Leavenworthia alabamica by measurement of the heritability of pollen tube number after self‐pollination. We tested for the role of the S ‐locus in this variation by sequencing seven S‐alleles from plants with high pseudo‐ SC ( PSC ) and testing for the co‐segregation of these alleles with PSC . We found a continuous distribution of PSC in all populations and 90% of plants exhibited PSC . The heritability ranged from 0.39 to 0.57. All seven S‐alleles from plants with high PSC exhibited trans‐specific polymorphism, and no stop codons were observed within the c . 600‐bp region sequenced. One of these S‐alleles was directly associated with the inheritance of PSC . We conclude that heritable variation in PSC is largely a result of genetic variation in the signaling cascade downstream of the S ‐locus reaction, together with the presence of one leaky S‐allele.