The writers of popular forensics drama franchise CSI would be well advised to read Genome Biology today, as we publish an article that employs a widely used epigenetics assay to show that age can be predicted with reasonable accuracy from pretty much any human DNA sample, so long as it is sourced from healthy tissue.

In other words, a swab of the perp's DNA, even if not matched to an individual on a database, could yield seriously good clues about the age of a suspect, alongside what the wiliest of TV detectives have already shown we can determine about gender and obscure genetic diseases.

Incredibly, the 'epigenetic clock' characterized by UCLA biostatistican Steve Horvath, from which he develops an 'age calculator' computer program, even works on chimpanzees. Which means there's no more hiding from the law for chimp criminals.

The science bit

More important than the implications for fictional forensics, the epigenetic (that is, DNA methylation) signatures uncovered by Horvath as corresponding to age will form the basis of further study on why these regions change over time and what the functional consequences might be.

Application of the age calculator to a large number of DNA methylation datasets from disease samples shows that the epigenetic clock is thrown off kilter in many cancers, with an especially notable acceleration in breast tumors.

What we don't yet know is whether these changes in DNA methylation are causative or symptomatic of human disease. In a Q&A with Biome magazine, Horvath raises the intriguing possibility that 'age acceleration may protect us from cancer', offering in support of this idea his finding that cancers with an accelerated epigenetic clock tend to have fewer somatic mutations.

Got data? Become a sleuth

Horvath's article is accompanied by an R code and idiot proof tutorial for those wanting to try out the age calculator for themselves.

All you need is some data from an Illumina Infinium 27k or 450k DNA methylation array.

If you don't have any of these data in your own possession, you will find many publicly available examples for download in the GEO data repository.

Before embarking on your detective work, you may wish to browse more Genome Biology articles on DNA methylation and aging, which we have grouped together here.