Evonne Low

Contact:
School of Biological Sciences,
Victoria University of Wellington,
Wellington.

Supervisors:
Prof. Phil Garnock-Jones (VUW)
Dr. Linley Jesson (VUW)

In my PhD study, I am interested in identifying the selective forces that might favor or cause the establishment of a dimorphic breeding system and identifying the possible evolutionary pathways to sexual dimorphism in Hebe. These genetic and ecological factors may include high inbreeding depression, high selfing rates, habitat or other ecological conditions. In my research, I hope to be able to examine and unravel some of the complex correlations between breeding systems and various ecological, morphological factors in promoting the evolution of dioecy in Hebe. As gender in some of the Hebe spp. is a quantitative trait, the distinction between gynodioecious and dioecious is not completely clear cut, the transitional stages in the cosexuality to gynodioecy pathway of gender dimorphic evolution might hopefully be uncovered among the populations of Hebe spp. studied.

I will use a multidisciplinary approach in the study of New Zealand's endemic Hebe, using it as a model system in the evolution of plant breeding systems. Hebe, New Zealand's largest plant genus, has many practical advantages as a model for this study. Hebe is one of the few New Zealand plant groups where gender dimorphism has evolved autochthonously so, the examination of its evolution will enable the focus on selection pressures occurring in an easy defined geographic area such as New Zealand.

As phylogenetic analyses allow much more powerful inferences about the evolution of breeding systems than simple correlations, I will be examining ecological traits and breeding systems in a phylogenetic context. To facilitate my phylogenetic analyses, I will be building upon the molecular systematics work done by Steve Wagstaff and Dirk Albach on Hebe using molecular DNA sequencing techniques. Analyzing chloroplast sequences such as trnT-F, matK and atpB-rbcL intergenic region of Hebe, the analysis could further shed light to Hebe evolutionary trends. By linking phylogenetic, molecular and ecological methods, I would be able to address important questions and correlations on the evolution of gender in plants using Hebe as the model for analyses.