Abstract Detail

Population Genetics/Genomics

Swope, Sarah [1], Braasch, Joseph [2].

Covariation in genotype and soil chemistry in a rare serpentine endemic.

Serpentine soils are stressful places for plants to live due to high concentrations of toxic heavy metals and low concentrations of essential nutrients. Much work has shown that serpentine endemics have evolved repeatedly from non-serpentine progenitors. However, serpentine soil itself can vary dramatically in its chemistry, perhaps leading to adaptation to different patches of serpentine. We wanted to (1) quantify variation in serpentine soil chemistry at the only location where Calochortus tiburonensis occurs, and (2) determine whether we can detect any spatial genetic structure associated with soil chemistry. C. tiburonensis is a Threatened species that is endemic to a single hilltop in Marin County, CA. It is pollinated by generalist insects but relies on self-pollination frequently. We collected leaf tissue from plants growing in a range of soil chemistries across the entire range and used RAD-seqs to describe any spatial genetic structure. STRUCTURE analysis revealed the existence of a single cluster over the entire geographic distribution (~1.5 km). The Westward Ridge site displays the highest degree of variation in soil chemistry. NMS analysis shows that soil samples taken from this site are the most chemically different from each other despite the fact that they are also nearest one another on the ground. Consistent with this, the plants at this site show the greatest diversity of genotypes and highest levels of heterozygosity, suggesting that greater diversity may be required for the plant to survive on these highly variable soils. We are currently conducting reciprocal transplant experiments to determine if this reflects local adaption.

1 - Mills College, Biology, 5000 MacArthur Blvd, Oakland, 94613, United States
2 - University Of Arizona, Ecology And Evolutionary Biology, 1041 E. Lowell St., Tucson, AZ, 85721, United States

Keywords:
serpentine
endemic
soil chemistry
RAD-seq.

Presentation Type: Oral Paper
Session: POPGEN1, Population Genetics/Genomics I
Location: Tucson H/Starr Pass
Date: Monday, July 29th, 2019
Time: 9:15 AM
Number: POPGEN1006
Abstract ID:842
Candidate for Awards:None