Abstract Detail

Population Genetics/Genomics

Hernandez, Adriana [1], Landis, Jacob [2], Specht, Chelsea [3].

Testing the Ring Species Hypothesis with RAD-Sequencing and MinION Genome Sequencing in the California endemic Calochortus venustus (Liliaceae).

Ring species are an ideal demonstration of incipient speciation, in which a founding population spreads and adapts in localized subpopulations separated across a divide and forming a ring such that when the farthest extending subpopulations come into contact, they can no longer successfully interbreed. Calochortus venustus L., a California endemic bulbous lily, displays striking variation in floral pigmentation and patterning with phenotypic spatial distribution suggestive of a ring species experiencing sequential change in phenotypic variation from the founding population. Petals of individuals within a population can range in color from deep red, purple, bright pink, and blush pink to white, with variation in petal spots as well, while terminal populations have the least variation in floral color patterns. Preliminary analyses of 25 samples indicate that there is strong population structure as evidenced by genetic differentiation especially between northern and southern populations. Leaf tissue from 200 individuals spanning the natural geographic range around the central valley of California were collected in the field in 2018 and 2019 for DNA extraction, each with quantified data on floral phenotype. In order to test for genomic signatures of selection and speciation, a draft genome was assembled using long reads from an Oxford Nanopore minION. A RAD-Seq approach is then used to test the association of recorded floral phenotypic features with particular genotypes (SNPs), to infer population structure, and to characterize the evolutionary history among the identified populations. These findings will be used to propose conservation management plans for C. venustus populations with uniquely high levels of polymorphism, and to provide insights into how polymorphic traits may be best maintained - or how and why they are lost - across the California landscape.

1 - Plant Biology, Cornell University, School of Integrative Plant Science, 412 Mann Library Bldg. #506, Ithaca, NY, 14853, United States
2 - University of California, Riverside, Botany and Plant Sciences, Riverside, CA, 92521, USA
3 - Cornell University, Plant Biology, Ithaca, NY, 14853, USA

Keywords:
ring species
floral trait evolution
California Floristic Province
RAD-seq
minION genome sequencing.

Presentation Type: Oral Paper
Session: POPGEN1, Population Genetics/Genomics I
Location: Tucson H/Starr Pass
Date: Monday, July 29th, 2019
Time: 8:45 AM
Number: POPGEN1004
Abstract ID:846
Candidate for Awards:Margaret Menzel Award