Abstract Detail



Questioning Species and Species Complexes: A Colloquium in Honor of Dr. R. James Hickey

Barker, Michael [1], Baniaga, Anthony [1].

Potential homoploid and allopolyploid speciation in Selaginella of the Sonoran Desert.

Hybridization and polyploidization (whole genome duplication) are important evolutionary processes in vascular plants. An estimated 15% of vascular plant species are allopolyploids, whereas as many 30% may experience hybridization and introgression with a close relative. Homoploid hybrid speciation is known from fewer well documented examples, but it is not clear how rare it is in nature. Despite the frequency of allopolyploid speciation, it has never been observed to occur with homoploid hybrid species produced by the same parental cross. This lack of allopolyploid and homoploid hybrid speciation from the same parents limits our ability to understand the differential impacts of hybridization and genome duplication on plant biology. Here, we document a potential example of both types of hybrid species produced from hybridization of Selaginella arizonica and S. eremophila. In the transition zone between the Lower Colorado River Valley and Arizona Upland subdivisions of the Sonoran Desert, putative diploid hybrids and allopolyploids of these species are found. Based on morphological and karyotypic analyses, we find that these plants are intermediate between S. arizonica and S. eremophila. We confirmed their hybrid nature using a combination of transcriptome, genome, and ddRADseq data analyses. We also inferred the relative contributions of each parent and their distribution in both hybrid genomes. Our results have broad implications for our understanding of the ecological and evolutionary genetic processes that occur in nascent diploid and polyploid hybrid populations in natural conditions, and provide a new study system to understand plant evolution.


1 - University of Arizona, Department of Ecology & Evolutionary Biology, Tucson, AZ, 85721, USA
2 - University of Arizona, Department of Ecology & Evolutionary Biology, Tucson, AZ, 85721, USA

Keywords:
polyploidy
hybridization
Selaginella
speciation.

Presentation Type: Colloquium Presentations
Number: 0006
Abstract ID:919
Candidate for Awards:None


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