Abstract Detail

Hybrids and Hybridization

Mitchell, Nora [1], Whitney, Kenneth [2].

Some evidence for a positive relationship between hybridization and diversification across seed plant families.

Hybridization has experimental and observational ties to evolutionary processes and outcomes such as adaptation, speciation, and radiation. Although it has been hypothesized that hybridization and diversification are positively correlated, this idea remains largely untested empirically, and hybridization can also potentially reduce diversity. Here, we use a hybridization database on 170 seed plant families, life history information, and a time-calibrated phylogeny to ask 1) Are there associations between hybridization and diversification rates across seed plant families?, and 2) Do these associations persist when correlated life-history traits are included in the statistical models?
We used three different methods to estimate diversification rates (BAMM, Medusa, and the method of moments estimator) and two different metrics to measure hybridization within seed plant families (hybridization propensity and hybrid ratio). We conducted permutation tests and phylogenetic linear mixed effect modeling to estimate the relationships between hybridization and net diversification rates in a univariate context. We also incorporated two additional factors associated with both hybridization and diversification (perenniality and woodiness) into these models.
We found that diversification and hybridization were sometimes positively correlated, although the effect sizes were very small (hybridization explained only a small amount of overall variation in diversification rates). This relationship remained detectable when incorporating life history characteristics, and the estimated effects of life history and hybridization were comparable in magnitude. Three different scenarios may explain these findings: hybridization may drive diversification, diversification may drive hybridization, or both hybridization and diversification may jointly be driven by other factors. This broad phylogenetic approach presents evidence for the potential role of hybridization in diversification and sets the stage for investigative studies at finer taxonomic, temporal, or geographic scales.

1 - University Of Wisconsin - Eau Claire, Department Of Biology, 651 University Drive, 330 Phillips Hall, Eau Claire, WI, 54701, United States
2 - University Of New Mexico, Department Of Biology, Castetter Hall, Albuquerque, NM, 87131, United States

Keywords:
adaptive radiaion
Extinction
diversification
perenniality
woodiness
Speciation
traits.

Presentation Type: Oral Paper
Session: HH2, Hybrids and Hybridization II
Location: /
Date: Wednesday, July 21st, 2021
Time: 12:45 PM(EDT)
Number: HH2002
Abstract ID:150
Candidate for Awards:Margaret Menzel Award