Date of Thesis

Spring 2023


The Solanum dioicum clade is a group of Australian bush tomatoes consisting primarily of species native to Western Australia and the Northern Territory whose species delimitations tend to be quite unclear. Since David Symon’s monograph A Revision of the Genus Solanum in Australia was published in 1981, little additional progress has been made in clarifying these relationships. In this project, a population genomics approach was used to analyze the relationships and delimitations between three species within the S. dioicum clade: Solanum dioicum, S. carduiforme, and S. ossicruentum. The use of population genomics methods is advantageous to understanding the fine-scale genetic diversity and population structures of species. To complete this project, DNA extractions from 149 populations across 15 populations of the 3 aforementioned species were conducted prior to DNA sequencing, assembly, and data analyses that allowed the interpretation of these relationships. This project allows an improved understanding of the relationships and delimitations between species within the S. dioicum clade. Our results indicate that there is a clear separation between the three studied species, and multiple genetic clusters within the S. dioicum populations, some of which may be their own independent taxa. In the context of global climate change, documenting species populations, particularly those which are rare or previously undocumented, helps regions that need extra protection get the resources they need, thereby protecting the biodiversity and stability of these habitats. It is extremely difficult to obtain the necessary resources to protect species if they have not been named or correctly described.


Population genomics, Australia, Solanum, Dioecy, Species boundaries, Genotype-by-sequencing

Access Type

Honors Thesis

Degree Type

Bachelor of Arts



Minor, Emphasis, or Concentration

Literary Studies

First Advisor

Christopher T. Martine

Second Advisor

Tanisha M. Williams

Third Advisor

Melody P. Sain

Included in

Biology Commons