Scientists accurately predict age with saliva sample

June 22, 2011

Self-conscious about your age? Careful where you spit. UCLA geneticists now can use saliva to reveal how old you are.

The June 22 advance online edition of the Public Library of Science (PLoS) ONE publishes the findings, which offer a myriad of potential applications. A newly patented test based on the research, for example, could offer crime-scene investigators a new forensic tool for pinpointing a suspect's .

"Our approach supplies one answer to the enduring quest for reliable markers of aging," said principal investigator Dr. Eric Vilain, a professor of , pediatrics and urology at the David Geffen School of Medicine at UCLA. "With just a saliva sample, we can accurately predict a person's age without knowing anything else about them."

Vilain and his colleagues looked at a process called methylation – a chemical modification of one of the four building blocks that make up our DNA.

"While genes partly shape how our body ages, environmental influences also can change our DNA as we age," explained Vilain. "Methylation patterns shift as we grow older and contribute to aging-related disease."

Using saliva samples contributed by 34 pairs of identical male twins ages 21 to 55, UCLA researchers scoured the men's genomes and identified 88 sites on the DNA that strongly correlated methylation to age. They replicated their findings in a general population of 31 men and 29 women aged 18 to 70.

Next, the scientists built a predictive model using two of the three genes with the strongest age-related linkage to methylation. When they plugged in the data from the twins' and the other group's saliva samples, they were able to correctly predict a person's age within five years – an unprecedented level of accuracy.

"Methylation's relationship with age is so strong that we can identify how old someone is by examining just two of the 3 billion building blocks that make up our genome," said first author Sven Bocklandt, a former UCLA geneticist now at Bioline.

Vilain and his team envision the test becoming a forensic tool in crime-scene investigations. By analyzing the traces of left in a tooth bite or on a coffee cup, lab experts could narrow the age of a criminal suspect to a five-year range.

In a minority of the population, methylation does not correlate with chronological age. Using this data, scientists may one day be able to calculate a person's "bio-age" -- the measurement of a person's biological age versus their chronological age.

Physicians could evaluate the risk of age-related diseases in routine medical screenings and tailor interventions based on the patient's bio-age rather than their chronological age. Instead of requiring everyone to undergo a colonoscopy at age 50, for example, physicians would recommend preventive tests according to a person's bio-age.

"Doctors could predict your medical risk for a particular disease and customize treatment based on your DNA's true biological age, as opposed to how old you are," noted Vilain. "By eliminating costly and unnecessary tests, we could target those patients who really need them."

The UCLA team is currently exploring whether people with lower bio-age live longer and suffer less disease. They also are examining if the reverse is true -- whether higher bio-age is linked to a greater rate of disease and early death.

Related Stories

Recommended for you

Maternal diet may program child for disease risk, but better nutrition later can change that

October 20, 2017
Research has shown that a mother's diet during pregnancy, particularly one that is high-fat, may program her baby for future risk of certain diseases such as diabetes. A new study from nutrition researchers at the University ...

New gene editing approach for alpha-1 antitrypsin deficiency shows promise

October 20, 2017
A new study by scientists at UMass Medical School shows that using a technique called "nuclease-free" gene editing to correct cells with the mutation that causes a rare liver disease leads to repopulation of the diseased ...

Researchers find evidence of DNA damage in veterans with Gulf War illness

October 19, 2017
Researchers say they have found the "first direct biological evidence" of damage in veterans with Gulf War illness to DNA within cellular structures that produce energy in the body.

Researchers drill down into gene behind frontotemporal lobar degeneration

October 19, 2017
Seven years ago, Penn Medicine researchers showed that mutations in the TMEM106B gene significantly increased a person's risk of frontotemporal lobar degeneration (FTLD), the second most common cause of dementia in those ...

New clues to treat Alagille syndrome from zebrafish

October 18, 2017
A new study led by researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) identifies potential new therapeutic avenues for patients with Alagille syndrome. The discovery, published in Nature Communications, ...

Genetic variants associated with obsessive-compulsive disorder identified

October 18, 2017
(Medical Xpress)—An international team of researchers has found evidence of four genes that can be linked to obsessive-compulsive disorder (OCD). In their paper published in the journal Nature Communications, the group ...

0 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.