Phylogeography of Petalonyx crenatus (Loasaceae): Genetic Structure Across a Gypsum Archipelago

Renée Geyer, Oberlin College

Location

Virtual presentation

Document Type

Presentation

Start Date

4-27-2020 8:00 AM

End Date

5-2-2020 5:00 PM

Abstract

Gypsum soil exposures are found throughout the Chihuahuan Desert Region. Gypsum can be a harsh soil for plants to grow on and yet numerous plants species grow only on gypsum exposures. These species are referred to as gypsum endemics. Petalonyx crenatus is a gypsum endemic shrub that is found throughout western and central Coahuila, a state in northern Mexico. During the Pleistocene epoch this desert biome disappeared and was replaced by a cooler, wetter climate. Many desert plants could no longer survive in this new environment. Our hypothesis is that gypsum endemics survived this non-ideal habitat because competition from other plants was reduced on gypsum since gypsum is a challenging soil to grow on. If this is correct, then gypsum endemics will have high genetic diversity across their species. Sequences of chloroplast and nuclear DNA from 5-20 P. crenatus plants per population at different geographic locations were obtained and compared. It was found that there is high genetic diversity in P. crenatus among populations and low genetic diversity within populations. In the past, Oberlin graduate Sophie Everbach began this research with 4-6 individuals per population of Petalonyx crenatus and found high haplotype diversity indicating that our hypothesis is correct. Now, this research has been continued with more individuals per population and the hypothesis is still supported.

Keywords:

Phylogeography, Desert plants, Biology, Population genetics, Chloroplast, Academia, Phylogeny

Notes

Click here to view this poster at the Office of Undergraduate Research website from April 27-May 2, 2020.

Major

Biology

Project Mentor(s)

Michael Moore, Biology

April 2020

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Apr 27th, 8:00 AM May 2nd, 5:00 PM

Phylogeography of Petalonyx crenatus (Loasaceae): Genetic Structure Across a Gypsum Archipelago

Virtual presentation

Gypsum soil exposures are found throughout the Chihuahuan Desert Region. Gypsum can be a harsh soil for plants to grow on and yet numerous plants species grow only on gypsum exposures. These species are referred to as gypsum endemics. Petalonyx crenatus is a gypsum endemic shrub that is found throughout western and central Coahuila, a state in northern Mexico. During the Pleistocene epoch this desert biome disappeared and was replaced by a cooler, wetter climate. Many desert plants could no longer survive in this new environment. Our hypothesis is that gypsum endemics survived this non-ideal habitat because competition from other plants was reduced on gypsum since gypsum is a challenging soil to grow on. If this is correct, then gypsum endemics will have high genetic diversity across their species. Sequences of chloroplast and nuclear DNA from 5-20 P. crenatus plants per population at different geographic locations were obtained and compared. It was found that there is high genetic diversity in P. crenatus among populations and low genetic diversity within populations. In the past, Oberlin graduate Sophie Everbach began this research with 4-6 individuals per population of Petalonyx crenatus and found high haplotype diversity indicating that our hypothesis is correct. Now, this research has been continued with more individuals per population and the hypothesis is still supported.