The oldest giant tortoises are revealing their genetic secrets for living up to 250 years. They are animals that are in the range of human size. Female giant tortoises are about 250 pounds and male giant tortoises are about 500 pounds. There are other super long-lived creatures like whales and sharks. However, those larger creatures seem to be leveraging constant slight amounts of growth. Being in state of constant growth of 0.1 to 0.5% means that the body is constantly generating stem cells and having active regeneration.
The genome of Lonesome George was sequenced using a combination of Illumina and PacBio platforms. There was a lot of other sequencing and analysis.
An important trait of large, long-lived vertebrates is their need for tighter cancer protection mechanisms. This need for additional protection illustrates the deep relationship and interdependence between cancer and longevity. Notably, tumors are believed to be very rare in turtles. Therefore, researchers analyzed more than 400 genes classified in a well-established census of cancer genes as oncogenes and tumor suppressors. Although most presented a highly conserved amino acid sequence when compared with the sequences of other organisms, we uncovered alterations in several tumourigenesis-related genes.
Giant tortoises are among the longest-lived vertebrate animals and, as such, provide an excellent model to study traits like longevity and age-related diseases. However, genomic and molecular evolutionary information on giant tortoises is scarce. They describe a global analysis of the genomes of Lonesome George—the iconic last member of Chelonoidis abingdonii—and the Aldabra giant tortoise (Aldabrachelys gigantea). Comparison of these genomes with those of related species, using both unsupervised and supervised analyses, led us to detect lineage-specific variants affecting DNA repair genes, inflammatory mediators and genes related to cancer development. Our study also hints at specific evolutionary strategies linked to increased lifespan, and expands our understanding of the genomic determinants of aging. These new genome sequences also provide important resources to help the efforts for restoration of giant tortoise populations.