Transcriptome data from silica-preserved leaf tissue reveals gene flow patterns in a Caribbean bromeliad

Abstract

SummaryTranscriptome sequencing is a cost-effective approach that allows researchers to study a broad range of questions. However, to preserve RNA for transcriptome sequencing, tissue is often kept under special conditions, such as immediate ultracold freezing. Here, we demonstrate that RNA can be obtained from six-month-old, field collected samples stored in silica gel at room temperature. Using these transcriptomes, we explore the evolutionary relationships of the genusPitcairnia(Bromeliaceae) in the Dominican Republic and infer barriers to gene flow.We extracted RNA from silica-dried leaf tissue from 19Pitcairniaindividuals collected across the Dominican Republic. We used a series of macro-and micro-evolutionary approaches to examine the relationships and patterns of gene flow among individuals.We produced high-quality transcriptomes from silica-dried material and demonstrated that evolutionary relationships on the island match geography more closely than species delimitation methods. A population genetic examination indicates that a combination of ecological and geographic features are barriers to gene flow inPitcairnia.High-quality transcriptomes can be obtained from silica-preserved tissue. The genetic diversity amongPitcairniapopulations does not warrant classification as separate species, but the Dominican Republic contains several barriers to gene flow, notably the Cordillera Central mountain range.