CSIRO can now read the genetic 'clock' that predicts how long pests live

CSIRO postdoctoral fellow Dr Ben Mayne said understanding lifespan was critically important for conservation, biosecurity and wildlife management.

"If you know the lifespan of a certain species, you can work out how many times it can be reproductive," Dr Mayne said.

"From there you can start working out population sizes and population growth rates.

"For example, with cane toads, knowing their lifespan and how many times they are going to breed, you can better estimate where that population is going and how fast it's moving.

"You can better manage the species and how to tackle the situation from a biosecurity risk.

"The lifespan estimate gives a more rapid, detailed population model that allows you to determine which species have a higher risk of becoming invasive than others."

"Our method for estimating maximum natural lifespan is based on DNA. If a species' genome sequence is known, we can estimate its lifespan," Dr Mayne said.

"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 known lifespans from public databases such as NCBI Genomes and the Animal Ageing and Longevity Database.

Some of the results were spectacular.

"Using our method, we found the maximum lifespan of the Bowhead whale is 268 years, 57 years longer than people thought," Dr Mayne said.

They found Neanderthals and Denisovans had a maximum lifespan of 37.8 years, similar to modern humans living around the same time.

That natural lifespan lengthened over the centuries thanks to changes in lifestyle and more recent medical advances.

"There are many genes linked to lifespan, but differences in the DNA sequences of those genes doesn't seem to explain differences in lifespan between different species," Dr Mayne said.

"Instead, we think that the density of a special type of DNA change, called DNA methylation, determines maximum natural lifespan in vertebrates.

"DNA methylation does not change a gene's sequence but helps control whether and when it is switched on.

"Using the known lifespans of 252 different vertebrate species, we were able to accurately predict lifespan from the density of DNA methylation occurring within 42 different genes.

"These genes are likely to be good targets for studying ageing, which is of huge biomedical and ecological significance."