Unraveling the Evolutionary History of a Gypsum Endemic Genus

Science Center, Bent Corridor

Nerisyrenia (Brassicaceae) is a genus of 11 herbaceous species endemic to the Chihuahuan Desert. Nerisyrenia is a key lineage in the ongoing project to understand patterns of diversification on gypsum. Most species of Nerisyrenia are allopatric and are gypsophiles, meaning they live exclusively on gypsum substrate. Through DNA sequencing of the ITS gene region for approximately 80 individuals of Nerisyrenia, we generated the first comprehensive species-level estimate of phylogeny for the genus. While most species appear to be monophyletic or nearly monophyletic, N. camporum, a species that grows sympatrically with other species of Nerisyrenia, appears interspersed throughout the phylogeny. This suggests the possibility of widespread gene flow between N. camporum and other species of Nerisyrenia. The phylogeny also strongly supports the monophyly of Nerisyrenia and implies that the genus speciated rapidly.