Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 42

Changes in DNA sequence are not the only age‐associated genomic alterations. DNA methylation, histone modification, and chromatin remodelling (collectively referred to as epigenetic modifications, known to influence gene expression) are also features of ageing.¹⁵ Several groups have observed high correlations between methylation status of CpG islets and chronological age in human and other species and thus described DNA methylations clocks that can predict donor age with an average error <5 years.^28,29 Perhaps more interestingly, the difference between chronological age and age predicted by these clocks in older individuals (DNA methylation age or epigenetic age) was shown to be associated with cognitive and physical functions, frailty, and various age‐related diseases and to be an independent predictor of all‐cause mortality.^30‐32 DNA methylation of selected key regions of the genome could thus reflect biological age rather than chronological age. Nevertheless, to date, biological causes and consequences of these epigenetic modifications during the ageing process remain unclear.³³