Bite mark bacteria provide potential forensic clues

(Medical Xpress) -- Oral bacteria lifted from bite marks may provide a new source of clues for forensic experts, thanks to research projects completed by students at the Sir John Walsh Research Institute in the University of Otago's School of Dentistry.

Bite marks are often left on following assaults, particularly in sexually motivated attacks but Dr Geoffrey Tompkins, a molecular and senior lecturer at the School, says evidence based on the morphometric examination of the shape and size of those marks is increasingly being challenged in criminal courts.

“Bite marks have been used as evidence using morphometric analysis but there is no scientific evidence that people have unique dentition and there has always been some subjective element in matching bite marks to teeth” he says.

“But it appears that each person’s mouth has a unique collection of bacteria with their own distinct genotype, so the bacterial DNA profiles could potentially be matched and used as evidence.”

The dental school has now had a series of undergraduate dental summer studentships that have taken this concept and explored it.

Dr Tompkins says one of the potential problems is that don’t live for long outside the mouth, but a recently published paper by student Lillian Hsu showed that the DNA of dead streptococci can be recovered from bite marks to produce DNA profiles.

The technique used left potential for false positives but a more recent, as yet unpublished project, by Otago PhD candidate Darnell Kennedy, successfully used a more sophisticated means of DNA analysis.

“It is a much more accurate means of testing and much more robust statistically,” says Dr Tompkins.

The summer studentships have allowed the dental students involved to get a taste of molecular microbiology research.

Dr Tompkins says the latest findings are the third publication of research findings by undergraduate dental students exploring this concept at the School of Dentistry.

"I am extremely proud of the efforts of these students. To complete such projects in just 10 weeks and then get them published in scientific journals is quite an achievement."

Related Stories

The teeth of cadavers reveal their identity

date Jun 29, 2010

Researchers from the University of Granada, Spain, have shown that a person's dental patterns can be used as proof of their identity with the same degree of reliability as DNA testing, the method that forensic ...

Jaws -- 4 million BC

date Mar 16, 2010

It might sound like a mashup of monster movies, but palaeontologists have discovered evidence of how an extinct shark attacked its prey, reconstructing a killing that took place 4 million years ago.

Recommended for you

Increased morbidity, mortality in food system industries

date 19 minutes ago

(HealthDay)—Occupational morbidity and mortality are elevated across food system industries compared with nonfood system industries, according to a study published online May 12 in the Journal of Occupational an ...

Three issues to consider before selecting EHR

date 1 hour ago

(HealthDay)—Work flow, features and functionality, and technical infrastructure should all be considered in advance of selecting an electronic heath record (EHR) system, according to an article published ...

Research letter: Indoor tanning rates drop among US adults

date 2 hours ago

Indoor tanning rates dropped among adults from 5.5 percent in 2010 to 4.2 percent in 2013, although an estimated 7.8 million women and 1.9 million men still engage in the practice, which has been linked to increased cancer ...

Stunting remains a challenge in South Africa

date 3 hours ago

Stunting remains stubbornly persistent in South Africa, despite economic growth, political and social transitions, and national nutritional programmes, says a Wits-led research team.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.