According to Dr. Benjamin Mayne, an Environomics Future Science postdoctoral researcher at the Indian Oceans Marine Research Centre of CSIRO, it is crucial to understand lifespan in order for better wildlife management, bio-security, and conservation. The method used for the estimation of the maximum lifespan clock is mostly based on the DNA. Thus, the lifespan clock can be estimated with the help of the genome sequence of the species. When it comes to lifespan, there are many genes that are liked. However, there are differences in the DNA sequence of such genes which are not able to explain lifespan differences between various species.
The maximum natural lifespan of vertebrates is determined by the DNA methylation which is the density of the special type of change in DNA. Although DNA methylation is unable to change the sequence of a gene, it does help control when and whether it has been switched on. The lifespan clock of 252 different vertebrate animal species have been used to accurately predict the lifespan by relying on the DNA methylation density as it occurs in 42 different genes. Dr. Mayne and his colleagues had to use animal genomes with known lifespan clocks to calibrate the method.
Public databases like the Animal Ageing and Longevity Database as well as the NCBI Genomes database were useful when it came to providing information. Researchers used the human genome to find out that the maximum lifespan clock of humans is 38 years which is in line with the estimates regarding the lifespan of early modern humans. However, the natural lifespan of humans has almost doubled in recent centuries due to changes in our lifestyle and the advancements made in the field of medicine.
This discovery has allowed researchers to find out that the lifespan of extinct species as well such as Neanderthals and woolly mammoths. In the past, it had been difficult for researchers to determine the lifespan of most wild animals like fish and lone-living species. The same method had been used for finding out that the maximum lifespan for a Bowhead whale which turns out to be 268 years. Thus, a Bowhead whale lives 57 years longer as compared to what most people thought. On the other hand, extinct wooly mammoths are said to have lived for 60 years. To estimate the lifespan clock of the extinct wooly mammoth, a genome was assembled by researchers from the modern African elephant genome. Denisovans and Neanderthals had a maximum lifespan clock of 37.8 years which is similar to that of modern humans during that time. This research has been possible with the help of collaboration between the University of Western Australia and the scientists involved in the research from CSIRO.