Final answer:
The molecular clock concept is utilized in Horvath's clock, an epigenetic tool that measures DNA methylation to assess biological age and compare epigenetic drift across species. Such tools rely on statistical modeling and historical data to correlate epigenetic changes with environmental and historical events.
Step-by-step explanation:
The concept of a molecular clock is a tool used in evolutionary biology to estimate the time of divergence between species by analyzing DNA or protein differences and their mutation rates. Horvath's clock is an extension of this concept, applied to epigenetics, specifically focusing on DNA methylation patterns to assess biological age and epigenetic drift. This drift, which can accumulate due to various factors including environmental influences, lifestyle, and disease, is compared across different species to understand both their biological age and the effects of their environments. Such comparisons can be made across various organisms like mice, dogs, and humans to generate hypotheses on human health based on extrapolations of scientific investigations from model organisms.
To accurately measure epigenetic drift, researchers must rely on complex statistical modeling to account for the myriad of factors that influence DNA methylation patterns over time. Furthermore, one must consider the historical variability in mutation rates, as these can vary for different reasons and across different time periods. The integration of epigenetic data with the fossil record, cultural history, and other demographic records, as in the case of the Swedish town of Överkalix, can provide further insights into how epigenetics correlates with historical events and environmental changes.