How do some people live past 110 years old? Is it superior genes, clean living, good luck or some combination of those?

Scientists studying these "supercentenarians" said on Wednesday they sequenced the genomes of 17 people ages 110 to 116 to try to determine whether they possess genetic traits that may account for their membership in this exclusive club that worldwide includes only about 75 individuals, nearly all women.

"This marks the beginning of the search for key genes for extreme longevity," said Stuart Kim, a professor of developmental biology and genetics at Stanford University whose study was published in the scientific journal PLOS ONE.