Abstract Detail

Ecological factors that drive patterns of population genetic structure in plants

Gamba, Diana [1], Muchhala, Nathan [2].

Meta-analysis of population differentiation in plants reveals importance of latitude, mating system, growth form and pollination mode.

Evaluating the factors that drive the patterns of population genetic differentiation in plants is critical for understanding the process of speciation at its earliest stages and the basis of local adaptation. Previous studies have shown that mating system and correlated traits are significant predictors of population differentiation (F_ST). However, F_ST should also be affected by the amount of gene flow mediated by pollination and seed dispersal modes. Additionally, F_ST is expected to be higher in tropical regions. To test these ideas, we assembled a database from published studies of 337 species with data on F_ST and species traits and constructed models with a set of ecological predictors: mating system, growth form, pollination mode, dispersal mode and latitudinal region. We performed phylogenetically informed multiple regressions (PhyloLM) and compare them to linear models (LM). PhyloLM performed better than LM, except after adding the predictor region. Results show higher F_ST for tropical, mixed-mating, non-woody species pollinated by small insects, and lower F_ST for temperate, outcrossing trees pollinated by wind. Dispersal mode was not a significant factor for explaining F_ST. Region was the most important predictor, with higher population differentiation in the tropics and subtropics than in the temperate zones. Mating system and growth form followed in importance, with mixed-mating plants having considerably higher F_ST than outcrossing plants, and trees considerably lower F_ST than non-woody plants and shrubs. Pollination mode showed the lowest significant importance in our models; small insect pollination was associated with significantly higher population differentiation than both wind and vertebrate pollination, while the latter two did not differ. Our findings have important implications for understanding the basis of genetic divergence in seed plants, in a phylogenetic context. We provide robust evidence, across these hundreds of studies, of a global latitudinal pattern of F_ST variation in seed plants.

1 - University Of Missouri - St. Louis, Biology, 223R Research Hall, Biology Department, One University Blvd, St. Louis, MO, 63121, United States
2 - University Of Missouri - St. Louis, Biology Dept., R428 Research Hall, One University Blvd, St. Louis, MO, 63121, United States

Keywords:
population differentiation
latitudinal region
mating system
growth form
pollination mode
phylogenetic comparative methods.

Presentation Type: Colloquium Presentations
Session: CO11, Ecological factors that drive patterns of population genetic structure in plants
Location: Tucson I/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 8:15 AM
Number: CO11002
Abstract ID:515
Candidate for Awards:Margaret Menzel Award