RT Journal Article
SR Electronic
T1 Disruption of endosperm development is a major cause of hybrid seed inviability between <em>Mimulus guttatus</em> and <em>M. nudatus</em>
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 029223
DO 10.1101/029223
A1 Elen Oneal
A1 John H. Willis
A1 Robert G. Franks
YR 2015
UL http://biorxiv.org/content/early/2015/11/02/029223.abstract
AB Divergence of developmental mechanisms within populations may lead to hybrid developmental failure, and may be a factor driving speciation in angiosperms.We investigate patterns of endosperm and embryo development in Mimulus guttatus and the closely related, serpentine endemic M. nudatus, and compare them to those of reciprocal hybrid seed. We address whether disruption in hybrid seed development is the primary source of reproductive isolation between these sympatric taxa.M. guttatus and M. nudatus differ in the pattern and timing of endosperm and embryo development. Some hybrid seed exhibit early disruption of endosperm development and are completely inviable, while others develop relatively normally at first, but later exhibit impaired endosperm proliferation and low germination success. These developmental patterns are reflected in mature hybrid seed, which are either small and flat (indicating little to no endosperm), or shriveled (indicating reduced endosperm volume). Hybrid seed inviability forms a potent reproductive barrier between M. guttatus and M. nudatus.We shed light on the extent of developmental variation between closely related species within the M. guttatus species complex, an important ecological model system, and provide a partial mechanism for the hybrid barrier between M. guttatus and M. nudatus.