The clock is defined as an age estimation method based on 353 epigenetic markers on the DNA. The 353 markers measure DNA methylation of CpG dinucleotides. Estimated age ("predicted age" in mathematical usage), also referred to as DNA methylation age, has the following properties: first, it is close to zero for embryonic and induced pluripotent stem cells; second, it correlates with cell passage number; third, it gives rise to a highly heritable measure of age acceleration; and, fourth, it is applicable to chimpanzee tissues (which are used as human analogs for biological testing purposes). Organismal growth (and concomitant cell division) leads to a high ticking rate of the epigenetic clock that slows down to a constant ticking rate (linear dependence) after adulthood (age 20).^[10] The fact that DNA methylation age of blood predicts all-cause mortality in later life even after adjusting for known risk factors^[14][15] is compatible with a variety of causal relationships, e.g. a common cause for both. Similarly, markers of physical and mental fitness are associated with the epigenetic clock (lower abilities associated with age acceleration).^[21] It systematically underestimates age from older individuals.^[22]

Salient features of Horvath's epigenetic clock include its applicability to a broad spectrum of tissues and cell types. Since it allows one to contrast the ages of different tissues from the same subject, it can be used to identify tissues that show evidence of accelerated age due to disease.

Ну вот и пишут, что метод применим для сравнения типов тканей и клеток, 353 маркера. Такое исследование будет стоить тысяч 20-30 евро и неполное, а только какой-то определённой ткани, или 2.3 типов тканей.