Hello Dr. Soundarya,
I'll do my best. At least I will point you towards some resources.
You asked HOW can we study the dynamic patterns. There are too many techniques and technologies to mention in detail. I suggest you may wish to read this background on epigenetics. http://www.ncbi.nlm.nih.gov/books/NBK45 ... pigenetics
Your question may be about how scientists choose their experimental design. That would depend on the question being asked by the researchers. For example, just imagine seeing a methylation pattern in tumor samples distinct from healthy tissues. Then after drug treatment that tumor methylation pattern changes back to match healthy tissue methylation.
Please watch New England Biolab's youtube playlist of videos on Epigenetics. http://www.youtube.com/playlist?list=PL4DE3723C85863814
You may be most interested in the videos with Sriharsa Pradhan explaining Epigenetics.
The sequence of the human genome alone does not provide enough information to completely explain natural phenomenons, such as development and disease states. The utility in studying epigenetics is exemplified by its translation to cancer treatment. Please read information here on some clinical trials. http://www.standup2cancer.org/progress_ ... epigenetic
The progress has been very exciting!