Teeth may hold information

University of Otago dentistry student Joseph Foster (left) and one of his supervisors, Dr Geoffrey Tompkins, consider a proposed new way of extracting information from teeth. Photo by Peter McIntosh.

An imaginative new approach to DNA testing -using mineralised plaque found on ancient teeth - could provide unexpected insights into links between social groups in the early history of the Pacific.

DNA analysis of human bones found in ancient graves has already provided invaluable information about the ethnicity and origin of the Pacific's early inhabitants. But such methods cannot clarify the interaction between ethnically identical but geographically separate communities that existed at the same time.

The proposed new approach could provide more information about such interactions, according to Joseph Foster (22), an Otago student taking part in the research.

Mineralised bacterial plaque, which involves calcium phosphate and carbonate deposited on tooth surfaces, is called calculus or tartar. This can threaten gum health and today is removed from the teeth by dental hygienists and dentists.

But by preserving the DNA found in oral bacteria, such as streptococcal species commonly found in the mouth, the rock-hard calculus often attached to ancient teeth could show whether there were distinctive similarities in the patterns of such bacteria found in teeth located at different grave sites.

Such bacterial similarities could indicate links between individual family members as well as other links between geographically separate communities, partly arising from food sharing.

One of Mr Foster's supervisors, Dr Geoffrey Tompkins, a senior lecturer in oral sciences at the university School of Dentistry, said the new approach was still at an early stage, and still faced challenges, including in extracting the bacterial DNA and carefully removing the calcium before testing.

But early signs were encouraging, research was continuing and he was cautiously optimistic this could be developed as a new analytical method.

Mr Foster, who already has an Otago BSc in microbiology, has been investigating some of the basic science required, over the university summer holidays.

His research was backed by a $5000 scholarship, supported by the Otago Medical Research Foundation.

Mr Foster, who begins third-year dentistry studies this year, said the research had been "quite exciting", involving a new area of inquiry.

The research was co-supervised by Dr Tompkins and by Dr Jo-Ann Stanton and Dr Hallie Buckley, the latter both of the Otago anatomy and structural biology department, and arose from an earlier inquiry by Dr Buckley, who is a physical anthropologist involved in early Pacific studies.

Two hundred research scholarships of various kinds have been provided to Otago health science students over the summer holidays.

- john.gibb@odt.co.nz