Delving Deeper into Identification
The Queensland Museum Network is well known as the caretaker of world class collections that represent our natural and cultural environments, however, we are also an active research institution that brings together modern analytical techniques with the expertise of our internationally recognised scientists.
This means that the Queensland Museum Network is one of Australia’s leading institutions aiding scientific discovery through identifying and describing species. Much of our biodiversity research utilises genetic data generated in the Molecular Identities Laboratory that was established at the Queensland Museum & Sciencentre in 2002. The primary aim of the work conducted in this facility is to use DNA (deoxyribonucleic acid) to help identify new and existing species and to understand their evolutionary relationships.
In living organisms DNA is not a single molecule but rather a pair of molecules entwined in the shape of a double helix. The primary role of DNA is the long term storage of the instructions needed to make proteins and other structural components of living organisms. The DNA segments that code those instructions are called genes. Thousands of genes are organised into structures called chromosomes. The set of chromosomes within a cell is called the genome. A very simplified way to think about genes and proteins is like building a house: genes act as the house’s architectural blueprint and the proteins as the bricks and mortar that are used to build it. However, just like every other aspect of biology, the way the genetic code and cells operate is far more complex than we ever anticipated and the way our genetic ‘blueprint’ is interpreted (or expressed) is determined by many internal and external influences.
Traditionally taxonomists use morphological characters (what organisms look like – including cellular, internal and external features) to identify and understand the relationships among species. There are, however, a number of problems inherent in solely using morphology to classify organisms. For example, unrelated organisms can independently evolve very similar features as a result of having to adapt to living in similar habitats. A classic example is the dorsal fin and torpedo-like body shape of ichthyosaurs (extinct marine reptiles), sharks (fish) and dolphins (mammals). Another challenge is that some species are superficially indistinguishable from others resulting in what is known as “cryptic species.” These issues can lead to two or more species being incorrectly classified as one.
Genetic analyses have now become commonplace in scientific research conducted at museums. Queensland Museum Network scientists use DNA to complement our biodiversity research programs in taxonomy (species identification) and systematics (species inter-relationships) to help objectively identify, name and classify new species. By comparing DNA sequences from different organisms and measuring the number of changes (mutations) between them, it is possible to determine if species are closely or distantly related. DNA does not replace classical morphology-based taxonomic studies but works as a valuable complement to them. Since all biological life forms have DNA or genetic material of some sort, the research in the lab involves all curatorial staff that work with different animal groups regardless of their particular area of expertise.
In addition to our taxonomic and systematic research, we have used genetic data to address a vast array of biological questions spanning marine, fresh water and terrestrial environments. These include DNA diagnostics of parasitic diseases which are important for aquaculture and commercial fisheries; the discovery of a unique system of sex determination in Australian brush turkeys; and the identification of patterns and levels of migration (gene flow) occurring among populations of highly endangered, tiny aquatic snails living in artesian springs in arid central Australia.
In recent years, Queensland Museum & Sciencentre has also established a Frozen Tissue Collection to complement our traditional specimen collections. This includes an ultra-cold freezer (-80o C) with storage capacity for up to 48,000 tissue samples. The collection now numbers over 15,000 tissue samples and is growing annually. These tissues are accessible to national and international researchers who wish to include Queensland and other Australian species in their genetic research projects.
Our in-house lab now attracts national and international collaborators, academic visitors, students and postdoctoral researchers. An important component of all our projects is mentoring and training students and visiting researchers in a wide variety of molecular techniques. The Molecular Identities Laboratory has resulted in a significant expansion of the Queensland Museum’s scientific capacity and infrastructure. It allows our expert scientists to delve deeper into biodiversity research to better understand the natural world.
Article originally appeared in Antenna, Queensland Museum Foundation Magazine, Winter 2105.
Contributor Dr Jessica Worthington Wilmer