Researchers at CSIRO, Australia’s national science agency, have discovered asimple way to estimate how long a species lives.
Using the human genome, the researchers found the maximum natural lifespan ofhumans is 38 years, which matches anthropological estimates of lifespan inearly modern humans. This has been extended over the centuries by changes inlifestyle and more recently by advances in medicine.
The discovery has revealed the lifespans of extinct species such as woollymammoths and Neanderthals. It also benefits fisheries and conservationmanagement, which until now have relied on observing how long animals live inthe wild.
Dr Ben Mayne, postdoctoral fellow with CSIRO’s Environomics Future SciencePlatform, said understanding lifespan is critically important forconservation, biosecurity and wildlife management.
“Our method for estimating maximum natural lifespan is based on DNA. If aspecies’ genome sequence is known, we can estimate its lifespan,” Dr Maynesaid.
“Until now it has been difficult to estimate lifespan for most wild animals,particularly long-living species of marine mammals and fish.”
To calibrate their method, the researchers used genomes of animals with knownlifespans from public databases such as NCBI Genomes and the Animal Ageing andLongevity Database.
“Using our method, we found the maximum lifespan of the Bowhead whale is 268years, 57 years longer than people thought,” Dr Mayne said.
“We discovered that extinct woolly mammoths lived for 60 years and therecently extinct Pinta Island giant tortoise from the Galapagos lived for 120years.”
To estimate lifespan for the extinct woolly mammoth, the researchers workedwith a genome assembled from the genome of the modern African elephant, whichlives for 65 years.
The genome of the Pinta Island giant tortoise is known from the last survivingmember of the species, Lonesome George.
They found Neanderthals and Denisovans had a maximum lifespan of 37.8 years,similar to modern humans living around the same time.
“There are many genes linked to lifespan, but differences in the DNA sequencesof those genes doesn’t seem to explain differences in lifespan betweendifferent species,” Dr Mayne said.
“Instead, we think that the density of a special type of DNA change, calledDNA methylation, determines maximum natural lifespan in vertebrates.
“DNA methylation does not change a gene’s sequence but helps control whetherand when it is switched on.
“Using the known lifespans of 252 different vertebrate species, we were ableto accurately predict lifespan from the density of DNA methylation occurringwithin 42 different genes.
“These genes are likely to be good targets for studying ageing, which is ofhuge biomedical and ecological significance.”
The research involved scientists from CSIRO and the University of WesternAustralia. The authors thank all individuals involved in the data creation,annotation and submission of the publicly available reference genomes used inthis study.
A genomic predictor of lifespan in vertebrates was published in ScientificReports this week: http://nature.com/articles/doi:10.1038/s41598-019-54447-w.
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