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Abstract Detail


Linan, Alexander [1], Schatz, George [2], Lowry, Porter [2], Miller, Allison [1], Edwards, Christine [3].

Mapping species boundaries: phylogenomics and patterns of gene flow in threatened Mascarene Diospyros (Ebenaceae).

On islands, where high rates of endemism are common as a result of adaptive radiation, closely related species frequently live in close proximity or in sympatry. Understanding species boundaries among such taxa is fundamental to our greater understanding of island species diversity. Furthermore, the ways in which interspecific hybridization is affected by both phylogenetic and physical distance among taxa is relevant for understanding the evolution of reproductive isolation. In this study, we focused on a clade of Diospyros endemic to the Mascarene Islands, a volcanic archipelago in the Indian Ocean comprising the islands Reunion, Rodrigues, and Mauritius. A total of 13 Diospyros species are endemic to the Mascarenes: Rodrigues and Reunion each have a single endemic species, and 11 largely sympatric, endemic species occur on Mauritius. The goal of this study was to use genetic data generated from multiple populations of each species to address three questions: 1) How do patterns of genetic variation correspond to species delimitations based on morphology? 2) What are the evolutionary relationships among Mascarene Diospyros? 3) How are patterns of interspecific gene flow shaped by phylogenetic relatedness and geographic proximity? We sampled multiple individuals from multiple populations of each of the 13 Mascarene species and used a 2bRAD-seq approach to genotype individuals. We analyzed SNP and DNA sequence data using population genomics and phylogenomics data analysis approaches, respectively. Genetic boundaries among species largely corresponded with species delimitations based on morphology. Phylogenomic analyses provided good resolution of the evolutionary relationships among species and revealed that although many occur in sympatry, hybridization appears to occur only between closely related species. These results have important implications for species conservation, as they will help ensure that efforts focus on taxonomically relevant species units.

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1 - Saint Louis University, Biology Department, 1 N Grand Blvd., St. Louis, MO, 63103, USA
2 - Missouri Botanical Garden, Africa and Madagascar Department, PO Box 299, St. Louis, MO, 63166, USA
3 - Missouri Botanical Garden, CCSD, PO Box 299, St. Louis, MO, 63166, USA

gene flow
Conservation genetics
species boundaries

Presentation Type: Oral Paper
Session: 33, Phylogenomics II
Location: Fort Worth Ballroom 4/Omni Hotel
Date: Wednesday, June 28th, 2017
Time: 8:30 AM
Number: 33003
Abstract ID:457
Candidate for Awards:Margaret Menzel Award

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