The human mouth is home to a teeming community of microbes, yet still relatively little is known about what determines the specific types of microorganisms that live there. Is it your genes that decide who lives in the microbial village, or is it your environment? In a study published online in Genome Research (www.genome.org), researchers have shown that environment plays a much larger role in determining oral microbiota than expected, a finding that sheds new light on a major factor in oral health.
Our oral microbiome begins to take shape as soon as we are born and sees a myriad of bacteria introduced to our mouth during childhood and later in life, yet little is known about whether nature (your genes) or nurture (your environment) has a stronger influence. Because of variations in the oral microbiome in both health and diseases like bacteremia and endocarditis, understanding the determinants of oral microbiota communities might lead to better prevention and treatment strategies.
In this study, a team of researchers from the University of Colorado sequenced the microbial DNA present in the saliva samples of a cohort of twins, and matched the DNA sequences in a database to determine which types of bacteria were present in each individual. In their data set, they utilized samples that were gathered over a decade of adolescence from the same individuals to observe how the salivary microbiome changes with time.
By comparing the salivary microbiomes of identical twins, who share the same genetic make-up and live in a common environment, the group found that their salivary microbiomes were not significantly more similar than the salivary microbiota of fraternal twins, who share only half of their genes, suggesting genetic relatedness is not as important as environment. "The conclusion that genetic relatedness plays at most only a small role in microbial relatedness was really a surprise," said Dr. Ken Krauter, senior author of the study.
"We were also intrigued to see that the microbiota of twin pairs becomes less similar once they moved apart from each other," added Simone Stahringer, first author of the study, explaining further evidence for the influence of environment on oral microbiota. Interestingly, in the samples obtained from the same individuals over time, they found that the salivary microbiome changed the most during early adolescence, between the ages of 12 and 17. This suggests that factors such as puberty or prominent behavioral changes at this age might be important.
Krauter explained that their work uncovered another unexpected finding, that there is a core community of bacteria that are present in nearly all humans studied. "Though there are definitely differences among different people, there is a relatively high degree of sharing similar microbial species in all human mouths."
The authors suggested that this report has established a framework for future studies of the factors that influence oral microbial communities. "With broad knowledge of the organisms to expect to find in mouths," said Krauter, "we can now better understand how oral hygiene, environmental exposure to substances like alcohol, methamphetamines and even foods we eat affect the balance of microbes."
Stahringer SS, Clemente JC, Corley RP, Hewitt J, Knights D, Walters WA, Knight R, Krauter KS. Nurture trumps nature in a longitudinal survey of salivary bacterial communities in twins from early adolescence to early adulthood. Genome Res doi: 10.1101/gr.140608.112.
Cold Spring Harbor Laboratory: http://www.cshl.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Evidence of an ancient settlement was found in the most inaccessible forest in Central America
Strong drugs are rarely warranted to control the behavior of dementia patients, specialists say. But antipsychotic medicine is being overprescribed, and not just among residents of nursing homes.
Scientists are refining what constitutes "normal"
Bumblebees can recall which flowers yield nectar, but like people they can get mixed up – leading them to home in on flowers they have no experience of
Brain cells that help us predict the intentions of others before they've actively made a decision have been discovered in monkeys
Experiments in mice suggest that treatment of haemophilia could be more successful if the baby's immune system is primed while in the womb
Scientists have recovered cultivated wheat DNA from an 8,000-year-old submerged site off the British coast. The finding suggests hunter-gatherers were trading for the grain long before they grew it.
An exciting fossil find in China points to a 525-million year old sea-dweller who used its new backbone to swim nimbly away from predators
Birds are dinosaurs. That’s a fact underscored by dozens upon dozens of discoveries in the last 30 years.