Most epigenetic clocks are produced by applying machine learning techniques to DNA methylation data derived from immune cells in reference blood samples taken from individuals of various ages. A clock is just an algorithm based on the fraction of genomes in the sample that are methylated at a number of specific Cpg sites. It is not too surprising to find that these clocks produce a different result when used on epigenetic data from tissue samples instead of blood samples, or that different tissues produce different results. After all, not all cell types have the same epigenetic respons…
Epigenetic Clocks Produce Different Results by Tissue Type
Most epigenetic clocks are produced by applying machine learning techniques to DNA methylation data derived from immune cells in reference blood samples taken from individuals of various ages. A clock is just an algorithm based on the fraction of genomes in the sample that are methylated at a number of specific Cpg sites. It is not too surprising to find that these clocks produce a different result when used on epigenetic data from tissue samples instead of blood samples, or that different tissues produce different results. After all, not all cell types have the same epigenetic respons…