Oliver White

 

Email: oww1v14 [at] soton.ac.uk

PhD student.

Supervised by Mark Chapman and Mark Carine (Natural History Museum) with Thomas Ezard.


The evolutionary consequences of hybridisation are varied, ranging from being of little consequence to the origin of an entirely new species. My research is focused on hybrid speciation, an evolutionary phenomenon that is particularly frequent in flowering plants and often associated with a change in ploidy level (polyploid speciation). However, a hybrid species can also originate without a change in chromosome number (homoploid hybrid speciation) if the hybrid exhibits adaptations to a novel environment.


My PhD project is focused on a genus of flowering plants called Argyranthemum (Asteraceae), endemic to the oceanic archipelagos of Madeira, Selvagens and the Canary Islands in the North Atlantic Ocean. Composed of 25 species, it is an exemplary example of an evolutionary radiation that is typical of remote oceanic islands. Argyranthemum also provides a well-documented case of homoploid hybrid speciation with A. sundingii and A. lemsii both derived from a cross between A. broussonetii and A. frutescens.


Cases of homoploid hybrid speciation are ideal biological scenarios to investigate the intersection between hybridisation, adaptation, reproductive isolation and speciation. Using Next Generation Sequencing to assay the expressed portion of the genome (the transcriptome), this project will investigate the genetic causes and consequences of homoploid hybrid speciation. For example, detecting differentially expressed loci that underlie adaptive divergence and identifying loci with non-neutral patterns of sequence polymorphism such that we can infer natural selection has taken place. In the past, such analyses were only possible for model organisms; however one can now study non-model organisms, in prime ecological and evolutionary scenarios, to investigate the genetic control of phenomena such as homoploid hybrid speciation.