December 19, 2018
38 years - But Our Life Expectancy Has More Than DOUBLED Over the Centuries Thanks to Lifestyle Changes and Advances in Medicine
* Australian scientists at CSIRO worked out animals' lifespan using 42 genes
* Using the human genome, the found the natural lifespan of humans is 38 years
* The bowhead whale, which is the longest-living mammal, can live for 268 years
PUBLISHED: 11:00 EST, 12 December 2019 | UPDATED: 12:23 EST, 12 December 2019
Humans have a maximum natural lifespan of only 38 years, according to researchers, who have discovered a way to estimate how long a species lives based on its DNA.
Scientists at Australia's national science agency have developed a genetic 'clock' computer model that they claim can accurately estimate how long different vertebrates are likely to survive - including both living and extinct species.
Using the human genome, the researchers found that the maximum natural lifespan of humans is 38 years, which matches anthropological estimates of lifespan in early modern humans.
They found Neanderthals and Denisovans had a maximum lifespan of 37.8 years, similar to modern humans living around the same time.
The reason the life expectancy of modern humans is more than double that length is down to advances in living standards and modern medicine, according to the researchers.
Scientists at Australia's national science agency have developed a DNA-based lifespan 'clock' that they claim can accurately estimate how long different vertebrates are likely to survive
Researchers found the maximum natural lifespan of humans is 38 years, which matches anthropological estimates of lifespan in early modern humans
Neanderthals and Denisovans, our early ancestors, had a maximum lifespan of 37.8 years, similar to modern humans
HOW LONG DO SPECIES LIVE?
1.1 years: Turquoise kill fish
19.8 years: African bullfrog
20 years: Passenger pigeon, African wild dog
23 years: Little bush moa
27 years: European turtle dove
37.8 years: Neanderthals and Denisovans
38 years: Humans
60 years: Woolly mammoth, straight-tusked elephant
120 years: Pinta Island giant tortoise
205 years: Rough eye rockfish
268 years: Bowhead whale
'Our method for estimating maximum natural lifespan is based on DNA, said Dr Mayne, of Australia's government science agency CSIRO (Commonwealth Scientific and Industrial Research Organization).
'If a species' genome sequence is known, we can estimate its lifespan. Until now it has been difficult to estimate lifespan for most wild animals, particularly long-living species of marine mammals and fish.'
As well as humans and human ancestors, the researchers tested their genetic clock on the genomes of other vertebrates, both living and extinct.
They found that the bowhead whale, which is the longest-living mammal on Earth, can live for 268 years - almost 60 years longer than previously believed.
This information tells us that these some of these Arctic mammals alive today may have been born before Queen Victoria even came to the throne and around the time Captain Cook first arrived in Australia.
It would explain why a bowhead whale found by Eskimos in 2007 had part of an antique harpoon lodged inside it, thought to have been made in the 19th century.
The CSIRO team took genomes of animals with known lifespans from public databases such as NCBI Genomes and the Animal Ageing and Longevity Database.
Scientists worked out animals’ lifespan by looking at a chemical process called ‘methylation’ which switches genes on or off.
As living things age, this goes haywire, with errors creeping in on specific genes, which can be used to work out how old an animal was when it died.
The bowhead whale can live 268 years, the study revealed, meaning existing species may have been in the ocean before the Victorian era
To estimate lifespan for the extinct woolly mammoth, the researchers worked with a genome assembled from the genome of the modern African elephant, which lives for 65 years
Benjamin Mayne and his colleagues used the genomes of 252 vertebrate species with known lifespans to identify the 42 genes that could help predict other lifespans.
For example, using the genome of the African elephant and its average lifespan of 65 years as a reference, the authors used their model to estimate that both the woolly mammoth and the straight-tusked elephant had a lifespan of 60 years.
The model estimated the lifespan of the extinct Pinta Island giant tortoise was 120 years.
Its genome is known from the last surviving member of the species, known as 'Lonesome George', whose death in the Galapagos Islands seven years ago made them extinct.
Understanding the natural lifespan is important for conservation, bio-security and wildlife management, said the researchers.
It also provides a more accurate way of calculating lifespan than previous methods that involved observing how long animals live in the wild and could help to work out animals' risk of extinction.
W. O. Belfield, Jr.