Learning About Aging From Comparative Studies

Studies concentrating on a small number of model organisms have figured strongly in recent biogerontological

Figure 20.5. A hypothetical scheme for the mechanism of lifespan regulation and evolution. (A) Evolved intraspecific differences in lifespan between parasitic and free-living adults are generated by differences in gene expression, regulated by endocrine and cellular signalling systems via regulated transcription factors. We propose that, as in C. elegans (Murphy et al., 2003), parasitic adult longevity in S. ratti results from up-regulation of longevity assurance genes and down-regulation of genes which promote aging. A arrows = stimulation, and T bars = inhibition. (B) Potentially, differences in aging rate between species may evolve via similar mechanisms. Here, the environment of an ancestral species changes, such that the extrinsic mortality rate is lowered, and selection against deleterious late-life effects is increased. This leads to the evolution of slower aging and increased longevity, which might occur via alterations in regulation of longevity assurance and aging genes. This predicts that several types of gene are likely to be altered during lifespan evolution: those encoding endocrine, signalling proteins and transcription factors. In (B), asterisks represent alterations in the trait resulting from random mutation, and selection.

Endocrine/ signalling

Free-living development

Parasitic development

Free-living development

Parasitic development

Endocrine/ signalling

How to Stay Young

How to Stay Young

For centuries, ever since the legendary Ponce de Leon went searching for the elusive Fountain of Youth, people have been looking for ways to slow down the aging process. Medical science has made great strides in keeping people alive longer by preventing and curing disease, and helping people to live healthier lives. Average life expectancy keeps increasing, and most of us can look forward to the chance to live much longer lives than our ancestors.

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