Abstract

Once thought to be an evolutionary dead-end, hybridization is now being detected in genomes across kingdoms, perhaps even playing an integral role in evolution. In chapter 1, I investigated the potential influences of hybridization on the evolution of a group of vagrant, asexual species in the Rhizoplaca melanophthalma species group. I sequenced the mitochondrial and nuclear genomes of 55 specimens and found well-supported nuclear phylogenies of both datasets. There were, however, multiple instances of discordance between the mitochondrial and nuclear trees, which can be caused by hybridization. PhyloNet and ABBA-BABA also detected widespread hybridization among this group. In chapter 2, I shifted to the Holarctic clade of lichen-forming fungi in Xanthoparmelia to characterize gene tree conflict and investigate the potential for hybrization. Here, I used three different tests for hybridization that account for incomplete lineage sorting "ABBA-BABA, PhyloNet, and SplitsTree" as well as PhyParts to characterize gene tree conflict. Like the Rhizoplaca species group, widespread hybridization was detected in the Holarctic clade despite robust phylogenies. My research underscores the value of investigating hybridization when studying species boundaries and evolutionary history.

Degree

College and Department

Life Sciences; Biology

Rights

https://lib.byu.edu/about/copyright/