Barbara Briggs: Detective botany and DNA

Dr Barbara Briggs is one of Australia’s leading botanists. She assisted police with a kidnapping-murder case in the 60's, described and reclassified 80 species and performed ground-breaking research into botanical evolutionary relationships during her 59 years at the Royal Botanic Garden Sydney.

Following in the footsteps of her mother, who in 1914 was the first woman in Australia to graduate with a Physics degree, Barbara completed her PhD at the University of Sydney in 1960. Her thesis was titled ‘Studies in the experimental taxonomy of Ranunculus and Darwinia.’ In 1959, a 24-year-old Barbara started her first day as a botanist at the Royal Botanic Garden Sydney and never looked back. 

Detective botany helps solve a kidnapping-murder case

In 1960, an eight-year-old Graeme Thorne was abducted in Sydney after leaving home for school. Graeme Thorne’s parents, Bazil and Freda Thorne, had won in an Opera House lottery and a man with a noticeable foreign accent telephoned the Thorne household claiming he had Graeme and demanded £25,000.

Over the weeks since he went missing, public appeals were made and police chased various other leads. Unfortunately, nearly six weeks after the kidnapping, Graeme Thorne’s body was discovered wrapped in a blanket and hidden on vacant land in Grandview Grove, Seaforth in Sydney.

Tiny botanical clues

There were a variety of clues from the forensic examination of the blanket, including some tiny plant fragments. After just one year of working as a botanist at the Royal Botanic Garden Sydney, Barbara was assembled into a team of detective botanists tasked with assisting police in the kidnapping-murder case. Barbara and her colleagues were each given a different plant fragment and were tasked to identify them.

“Remember, we didn’t have DNA technology in the 60’s, but I was still able to identify my tiny piece of plant material,” Barbara said.

“Although mine ended up being a common native species, it did teach me that a tiny leaf fragment could be identified when you really try,” Barbara said.

Tiny fragments leads to big trees

It was another scientist in the team that ended up identifying the leaf fragments that belonged to two tree species, Chamaecyparis pisifera and Cupressus glabra, that were not present at the vacant lot where the body was found.

“Although such trees could be found growing in many people's yards, the combination of the two together was rare,” Barbara said.

Barbara’s identification, and that of her colleagues, narrowed the search for the murderer. The botanical clues allowed police to search for a house with these two trees growing, along with other leads: a blue car and pink mortar. Following a tip-off from a postman, a house was identified at 28 Moore Street in the suburb of Clontarf where a Hungarian immigrant named Stephen Bradley lived.

Killer sentenced

Bradley had left Australia a week earlier to Colombo but after weeks of legal wrangling, he was extradited to Australia and made a verbal confession. The high-profile trial for murder lasted nine days and he was eventually sentenced to penal servitude for life.

“Although we couldn’t save Graeme Thorne, this case sparked the beginning of modern forensic investigation in Australia,” Barbara said.

An even bigger investigation: mapping the tree of life

Barbara has always been interested in plant evolution but when she began her career as a botanist at the Royal Botanic Garden Sydney in 1959, there was no DNA technology. DNA is the hereditary or genetic material present in all cells, that carries information for the structure and function of all living things – including plants.

This game-changing research didn’t come along until the 1980’s and it was Barbara and her colleagues who were responsible for introducing DNA technology to the Garden’s science programs. She has been responsible for ground-breaking research into botanical evolutionary relationships and is particularly interested in plants in the southern hemisphere.

“We know that southern continents were once united as the supercontinent Gondwana so when I went to Madagascar I was interested to see links between plants of the southern hemisphere,” Barbara said.

“By analysis of DNA sequences, we can obtain data to construct family trees of evolutionary relationships of living organisms of all sorts.

“Combining these relationship trees with the fossil record gives us a chronology of evolution. Linking this with the story of continental movement leads to hypothesis of how plants moved around the southern lands.

"I have been fortunate to work in biology during the time when the use of DNA methods has given a far more complete and robust knowledge of evolutionary relationships than I ever expected to see,” Barbara said.

59 years of growing with the Garden

People nowadays hop from job to job, but even after retiring, Barbara has remained at the Garden as an Honorary Research Associate. Barbara has been performing research at the Garden for 59 years and values the diversity of the organisation.

“It is not only a place for science, but also history and education and it is a valued space for Sydney people and international visitors,” Barbara said.

“Had it been a farm, I believe it would have been subdivided and sold for building, which would have been a great shame,” Barbara said.

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