Researchers looked at the genome of some of the world's oldest living people but were unable to uncover the secrets behind their longevity.

The research team looked at 20 genomes, but did not notice a protein-altering variant associated with a longer life span, PLOS reported.

"We found no significant evidence of enrichment for a single rare protein-altering variant or for a gene harboring different rare protein altering variants in supercentenarian compared to control genomes," the researchers wrote in their study abstract.

Supercentenarians are people who live beyond 110 years of age, and only 74 are alive in the world today (22 of whom live in the United States). To make their findings the researchers performed whole genome sequencing on 17 supercentenarians to see if they could find a genetic reason behind their exceptionally long lifespans.

The researchers did find one supercentenarian had a genetic variant related to a heart condition that had very little effect on his health considering he reached such and elderly age. The researchers noted that it is recommended by the American College of Medical Genetics and Genomics to report this instance as an incidental finding.

While the researchers did not find a significant association with extreme longevity, the researchers published their genome findings so they will be available as a resource for future researchers looking at the "genetic basis" of longevity.

The work was supported by the Ellison Medical Foundation/American Federation for Aging Research Fellowship, Stanford Dean's Fellowship, The Paul Glenn Foundation Biology of Aging Seed Grant, National Institute of General Medical Sciences Center for Systems Biology and the University of Luxembourg - Institute for Systems Biology Program.