Premium
Genetic loci with parent‐of‐origin effects cause hybrid seed lethality in crosses between Mimulus species
Author(s) -
Garner Austin G.,
Kenney Amanda M.,
Fishman Lila,
Sweigart Andrea L.
Publication year - 2016
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.13897
Subject(s) - biology , genetics , hybrid , reproductive isolation , evolutionary biology , botany , population , demography , sociology
Summary In flowering plants, F 1 hybrid seed lethality is a common outcome of crosses between closely related diploid species, but the genetic basis of this early‐acting and potentially widespread form of postzygotic reproductive isolation is largely unknown. We intercrossed two closely related species of monkeyflower, Mimulus guttatus and Mimulus tilingii , to characterize the mechanisms and strength of postzygotic reproductive isolation. Then, using a reciprocal backcross design, we performed high‐resolution genetic mapping to determine the genetic architecture of hybrid seed lethality and directly test for loci with parent‐of‐origin effects. We found that F 1 hybrid seed lethality is an exceptionally strong isolating barrier between Mimulus species, with reciprocal crosses producing < 1% viable seeds. This form of postzygotic reproductive isolation appears to be highly polygenic, indicating that multiple incompatibility loci have accumulated rapidly between these closely related Mimulus species. It is also primarily caused by genetic loci with parent‐of‐origin effects, suggesting a possible role for imprinted genes in the evolution of Mimulus hybrid seed lethality. Our findings suggest that divergence in loci with parent‐of‐origin effects, which is probably driven by genomic coevolution within lineages, might be an important source of hybrid incompatibilities between flowering plant species.