11/18/2023 0 Comments Animal age 66 diedYet, despite this profound practical importance, lifespan is poorly characterised for most wild animals because it is difficult to estimate 28. Consequently lifespan is central to estimating risk of animal extinction 25, evaluating biosecurity risks 26 and estimating the sustainable yield in fisheries and other harvested organisms 27. The differences in lifespan between species has ecological significance because age regulates fundamental aspects of animal life cycles and demography such as probability of mortality 24. In mammals, the forest shrew ( Myosorex varius) has one of the shortest reported lifespans at 2.1 years 23, whereas some bowhead whales ( Balaena mysticeta) have been reported to be older than 200 years 19, 23. In vertebrates, species such as the pygmy goby ( Eviota sigillata) live for only eight weeks 21, while the Greenland shark ( Somniosus microcephalus) may live for more than 400 years 22. Maximum lifespans differ greatly among species, even among fairly closely-related species 20. Alternatively, it is an accepted consensus value for the majority of individuals within a species 18, or is based on records from a small number of wild individuals that have an age estimate as a result of exceptional circumstances 14, 19. It is frequently the highest reported value for captive animals because of the difficulty in estimating age for wild individuals. Similar epigenetic clocks have been created in a range of mammal and bird species 13, 14, 15, 16, 17.Īlthough it’s often reported, maximum lifespan for a species is difficult to define. Individual human age, for example, can be predicted with great accuracy (R 2 = 0.92) in a range of tissues by an epigenetic clock 12. The observation that DNAm at promotor CpG sites can accumulate or decline predictably with age, over and above the more random process of epigenetic drift, has enabled the development of “clock like” biomarkers for age 9, 10, 11. This modification to DNA has the potential to regulate gene expression, including of genes critical for longevity, without altering the underlying sequence. DNAm of cytosine-phosphate-guanosine (CpG) sites, involves a covalent modification to cytosine to form 5-methylcytosine. Ageing is also associated with several epigenetic changes involving DNA methylation (DNAm) 7, 8. Longevity of individuals is strongly linked to specific alleles in genetic model organisms 4, 5, 6. Ageing involves the decline of diverse biological functions and the dynamics of this process limit a species’ maximum lifespan 3. Our lifespan clock provides a wholly new method for accurately estimating lifespan using genome sequences alone and enables estimation of this challenging parameter for both poorly understood and extinct species.īiological ageing is observed in almost all animal species 1, 2. The lifespan clock accurately predicts maximum lifespan in vertebrates (R 2 = 0.76) from the density of CpG sites within only 42 selected promoters. We also derive a predictive lifespan clock based on CpG density in a selected set of promoters. Using 252 whole genomes and databases of animal age and promotor sequences, we show a pattern across vertebrates. Furthermore, an analysis of mammals showed that the density of CpG sites in gene promoters, which are targets for DNA methylation, is correlated with lifespan. Ageing is associated with epigenetic changes involving DNA methylation. Ageing involves the decline of diverse biological functions and places a limit on a species’ maximum lifespan. Biological ageing and its mechanistic underpinnings are of immense biomedical and ecological significance.
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