Abstract Detail

Systematics

Liu, Michelle [1], Finch, Evan [1], Leatherman, Lila [1], Douglas, Norman [2], Flores-Olvera, Hilda [3], Ochoterena, Helga [4], Moore, Michael [1].

What can genetic diversity tell us about how gypsum endemic plants survived the Pleistocene? A test using multiple plant groups.

The Chihuahuan Desert region of the southwestern USA and northern Mexico is notable for having the highest number of gypsum endemic plant species (gypsophiles) in the world, with over 230 species from more than 35 families of plants that grow only on gypsum soils. Many of these gypsum endemic species belong to clades of gypsophiles that are geographically widespread in the Chihuahuan Desert and that are likely to have first appeared prior to the Pleistocene. Pleistocene full-glacial periods in the Chihuahuan Desert were characterized by increases in rainfall and decreases in temperature, leading to the replacement of desert scrub with grassland and savanna across most of the Desert region. However, we hypothesize that gypsophile populations were more resistant to Pleistocene climate changes, because gypsum is low in essential nutrients and forms a hard physical crust, making it very difficult for most plants to survive in. Hence gypsum communities may have experienced lower competition during full-glacial periods, leading to the greater survival of gypsophiles compared to desert plants off of gypsum. To test this hypothesis, we are exploring levels of genetic diversity in three plant groups with geographically widespread clades of Chihuahuan Desert gypsophiles, each of which likely evolved prior to the Pleistocene: the Anulocaulis (Nyctaginacae) gypsophile (2 gypsophiles); the Acleisanthes (Nyctaginacae) gypsophiles clade (5 gypsophiles); and Asteraceae subtribe Flaverinae, which consists of three different genera (Flaveria, Haploësthes, and Sartwellia) and has at least three different origins of gypsum endemism, including clades of gypsophiles in Haploësthes and Sartwellia. Using target sequence capture, we sequenced and assembled over 300 nuclear genes for at least 30 populations of each group. The resulting exon and partial intron sequences will be used to understand the phylogeography of these gypsophiles and to assess levels of gene flow among populations, which will enable us to determine whether these clades persisted broadly during the Pleistocene full-glacial periods or were reduced to one or more refugia.

1 - Oberlin College, Department of Biology, 119 Woodland Street, Oberlin, OH, 44074, United States
2 - University Of Florida, Biology, PO Box 118525, Gainesville, FL, 32611, United States
3 - Instituto De Biologia, UNAM, Departamento de Botanica, Apdo.Postal 70-367, Coyoacan, Mexico DF, 04510, Mexico
4 - Instituto De Biología, UNAM, Botanica, Depto Botánica-Apdo.Postal 70-367, Coyoacan, Mexico DF, 04510, Mexico

Keywords:
Gypsum
phylogeny
Nyctaginaceae
Asteraceae
Chihuahuan Desert
Target enrichment.

Presentation Type: Poster
Session: P3, Systematics Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3SY004
Abstract ID:452
Candidate for Awards:None