Abstract Detail

Hybrids and Hybridization

Ivey, Christopher [1], Habecker, Nicole [2], Bergmann, Jean-Phillipe [2], Ewald, Jacob [2], Coughlan, Jenn [3].

Porus species boundaries between Mimulus glaucescens and M. guttatus in Butte and Tehama counties, California.

The cohesion of recently diverged species is thought to be maintained by traits that reduce the chance of interbreeding with close relatives. Typically, barriers to reproduction are well-defined, or if not, species boundaries are indistinct. Mimulus glaucescens, which is endemic to Butte and Tehama counties, California, has long been recognized as distinct from its close relative, the widespread M. guttatus, based on vegetative characters, despite an unsettled taxonomy among other close relatives in the genus. Nonetheless, both species broadly co-occur, they both flower in the spring, their floral morphologies are similar, and fertile hybrids have been reported from earlier greenhouse studies – yet hybrids are rarely reported from field collections. Thus, barriers to reproduction are not obvious, despite what appear to be clear species boundaries. Field, greenhouse, and laboratory experiments were used to characterize multiple potential reproductive barriers between these taxa, but reproductive isolation was weak. Whole-genome sequence data support the monophyly of M. glaucescens, but also find introgression and interbreeding to be common. Thus, although these taxa are widely considered to be distinct species, the boundaries defining them as such appear to be poorly supported.

1 - California State University, Chico, Biological Sciences, 400 W 1st St., Chico, CA, 95929, United States
2 - California State University, Chico, Biological Sciences, 400 W. First St., Chico, CA, 95929, USA
3 - Yale University, Department of Ecology and Evolutionary Biology, New Haven, CT, USA

Keywords:
speciation
reproductive isolation
hybridization
introgression
monkeyflower
Mimulus
Erythranthe
species delimitation
Species Distribution Modeling
gene flow.

Presentation Type: Oral Paper
Number: HH2004
Abstract ID:525
Candidate for Awards:None