Eucalypt genomics

Speciation and hybridisation in woodland Eucalyptus

Eucalyptus offers an unique opportunity to investigate the sources of allelic variation underlying adaptive radiation. It is a species-rich (>700 species) genus, primarily consisting of essential foundation species on which entire ecosystems of interacting organisms depend. The box-ironbark eucalypt group has a central role in a number of protected communities (e.g. the Yellow Box-White Box-Blakely’s Red Gum Grassy Woodland). Many of its species co-occur over broad areas, creating replicated hybrid zones and the opportunity to investigate the relationship between divergence between species and local adaptation. Although many eucalypt species hybridise and some have become textbook examples, our understanding of the evolutionary significance and adaptive value of interspecific gene flow is limited. Our research uses whole-genome and reduced representation sequencing in the box-ironbark eucalypts to address fundamental evolutionary questions.

  • What is the history of hybridisation and gene flow between woodland eucalypt species?
  • Is the locally-adaptive variation identified by landscape genomics methods shared among species?
  • Is new, introgressed or standing genetic variation involved in local adaptation within species?
  • How does spatial scale affect the genomic structure of divergence?
This is an ARC Discovery Project being run in collaboration with Justin Borevitz and his lab at the Australian National University, with Dr Jasmine Janes at UNE.
Other collaborators on this project include Kevin Murray (ANU), Jeremy Bruhl (UNE), Rebecca Jordan (CSIRO), Ed Biffin (SA Herbarium), Gideon Bradburd (MSU), Khawla Alwadani (UNE) and Tim Collins (UNE).
Recent developments:
– Dr Jasmine Janes is finding evidence of extensive gene flow between species.
– Tim Collins has identified a putative hybrid species using morphology, phytochemistry and genotyping-by-sequencing for his Honours. Kevin Murray and Momena Khandaker are testing whether it is a distinct, stable species, and Momena is studying mating patterns in the zones of contact.
– Khawla Alwadani has found extreme phylogenetic discordance of chloroplast genomes with taxonomy and nuclear DNA groups.