No Correlation of Telomere Length with Longevity in Nematodes
Average telomere length in cells reflects some combination of cell division rates and cell replacement rates: telomeres shorten with each cell division until cells self-destruct because telomeres are too short, and replacements are generated with long telomeres by stem cells. The stem cell activity that delivers those replacements tends to decline with age, and so average telomere length tends to decrease as well. But this is highly variable between individuals and with circumstances such as illness, exercise, and so forth. Researchers only see the decline in statistics gathered across a large study population, making this a terrible measure of aging for any individual consideration. Added to this, for every paper to show some useful correlation for telomere length, there is another to show no useful correlation between teleomere length and measures of aging, such as this one that examines natural variations in telomere length and longevity in nematode worms:
Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length.
Our observation that considerable telomere-length variation in the wild isolate population exists allowed us to directly test whether variation in telomere length contributes to organismal fitness. We did not see any correlation between telomere length and offspring production, suggesting that fitness in wild strains is not related to telomere length. In contrast to findings in human studies, we did not identify a relationship between telomere length and longevity. Our results confirm past findings that telomere length is not associated with longevity in a small number of C. elegans wild isolates or laboratory mutants. In summary, this study demonstrates that a variant in pot-2 likely contributes to phenotypic differences in telomere length among wild isolates of C. elegans. The absence of evidence for selection on the alternative alleles at the pot-2 locus and the lack of strong effects on organismal fitness traits suggest that differences in telomere length do not substantially affect individuals at least under laboratory growth conditions.
Hi, interesting.
I guess I believe more in telomeres, they won't revert aging completely it's true; as in Elizabeth Parrish's case at BioViva; because of the damage she had already accumulated. But, in humans, they are still nonetheless an important marker of longevity. If we can remove all damages repeatedly to a decent percentage, thus rejuvenate 30 years, whether the telomeres are short or tall; then telomeres become a moot point.
Here in this study, it is flawed because they use nematodes, not humans, because the nematodes they verified live
20 to 30 days; basically regular wild types who barely live 30 days making their study results poor biased cherry picking.
You have to be careful with studies on telomeres in ultra short lived organisms. Like this, this study is invalid and unapplicable. Had they verified telomeres in a 10-fold long-lived mutant (age-1 mg44 f2) that lives 250 days vs a meager 30 days for wild type; then, then yes, I would of believed their results - which would have been different : the ultra-long lived mutant nematodes displays different telomeres loss dynamics, which it keeps taller and for a much longer period.
Agreed