Abstract Detail

Macroevolution

Hagen, Eric [1], Beaulieu, Jeremy [2].

Multivariate Approaches to Studying the Importance of Genome Size Evolution.

The extreme variation in genome size in plants has long fascinated biologists, but there is little evidence that genome size has any adaptive value. Several studies have investigated genome size evolution in plants, but many suffer from small sample sizes, sparse fossil data, a lack of multivariate framework, and inadequate consideration of phylogenetic non-independence. Using guard cell length as a proxy for genome size, we took a multi-pronged approach to explore diversity patterns associated with genome size in plants. We used the largest dataset of combined extant and fossil guard cell data to date. We collected data from several sources, including Cuticle Database and the collections of several museums, and conducted our own measurements. These were performed on thousands of guard cells from present-day plants as well as fossils possessing preserved cuticles, which must be present in order for guard cells to be measured. Using a linear relationship discovered by Beaulieu et al. (2008), we converted guard cell length measurements to genome size estimates. We averaged guard cell measurements from at least three specimens per species in order to determine the approximate genome size for each. We compared several methods of constructing trees, including testing how fossil placement affects tree relationships as well as how trees constructed based on traits compare to trees. We then tested for correlated evolution among the different traits, particularly focusing on the possible relationship between guard cell length and stomatal pore size, and how particular trait combinations impact diversification. One of our tests for correlated evolution, between GC content and genome size, is the first test of such a relationship in dicots. GC content scales quadratically with genome size in monocots, and recent work has suggested that higher GC content correlates with thermostability and tolerance for arid environments. Through these investigations, we hope to make strides in answering persistent questions surrounding the evolution of genome size in plants.

1 - University of Arkansas, Biological Sciences, 850 W Dickson Street, Science and Engineering Hall 715, Fayetteville, AR, 72701-1201, USA
2 - University of Arkansas, 850 W Dickson Street, Science and Engineering Hall 735, Fayetteville, AR, 72701-1201, United States

Keywords:
Genome size
polyploidy
comparative methods
guard cells
multivariate analyses.

Presentation Type: Poster
Session: P, Macroevolution Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PMC004
Abstract ID:836
Candidate for Awards:None