Deriving mammalian DNA methylation predictors of maximum lifespan, gestation period, and age at sexual maturity

A research team has discovered that there are epigenetic predictors of species lifespan and other traits in mammals. In their article published in the magazine Scientific progressthe group describes how they analyzed data stored in a database set up by the Mammalian Methylation Consortium, and what they learned in the process.

The team consists of biostatisticians, biological chemists and geneticists from the University of California and collaborates with colleagues from several other institutions in the US and one in the UK.

Previous research has shown that different mammals have vastly different lifespans; for example, humans live much longer than dogs or cats. But why this is the case has not been explained. In this new effort, the research team focused on epigenetics: the study of changes in organisms that are passed from generation to generation as a result of modification of gene expression, rather than gene mutations. Or more specifically, they looked at how epigenetic clocks can predict three life-changing traits: the duration of pregnancy, the duration of puberty and maximum lifespan.

To study such clocks, they accessed data from the Mammalian Methylation Consortium, specifically focusing on epigenetic modifications in 15,000 tissue samples collected from 348 mammalian species. They then developed several algorithms that could accept the data they collected and use it to make epigenetic estimates based on the three chosen criteria.

In running and tightening their algorithms, they found that they could use them as predictors of the lifespan of mammals not included in the database. Tests showed that they were very accurate.

The researchers then looked to see if there might be environmental factors that influence lifespan, such as diet, but found none. They found the same results when testing smoking, race, weight, cognitive function and metabolism. The only factor they found that made a difference was gender: females of all mammal species tended to live longer than males.

The team concludes by suggesting that lifespan in humans and other mammals is “strongly associated with an epigenetic signature.” One that is unique to each species and difficult to change.