In the adjacent photo, Edna Parker is seen holding a rose that she was given during a birthday party for her in Shelbyville, Ind., Friday, April 18, 2008. Parker, who was born April 20, 1893, is the oldest known human. She will turn 115 on Sunday, April 20, 2008. She was recognized by Guinness World Records as the oldest person living last August after the death of a Japanese woman four months her senior.(AP Photo/Darron Cummings)

Scientists are analyzing DNA samples from people crossing 110 years to find the clue for the causes of longivity. DNA samples of more than 100 supercentenarians is already in the research database. It is believed that the secret to a long life is a mix of genetics and environmental factors such as health habits. A research on about 1,500 centenarians also show that they appear not to dwell on stressful events.

Only 75 living people — 64 women and 11 men — are 110 or older, according to the Gerontology Research Group of Inglewood, Calif., which verifies reports of extreme ages.

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