Preface

A few decades ago, research in biological sciences, especially molecular biology and disease connection, was confined to research on prominent diseases and involved techniques like polymerase chain reaction (PCR) to study gene polymorphisms, underpin the genetic nature and heritability of certain diseases, study mutations in various forms of cancer, and so on. These approaches, although still relevant and significant, were not able to fully capture the underlying problems in various diseases and missed the mark on the role of "environmental influences" in various diseases, which we now understand to play a paramount role in propagating or sometimes even driving various diseases. In addition, these environmental influences also impact our overall wellbeing and play a huge role in all aspects of life, including longevity, stress levels, and responses to stress since these takes into account various unappreciated factors like the impact of social influences, diet, nature of work, exposure level to chemicals, environment, ethnicity, geographical location, climatic conditions, and so on. Our environmental influences encompass anything and everything from where we are located to what we do and how we are exposed to various conditions. In addition to affecting our well-being in a "transient" manner, these may also influence our health, well-being, and the likelihood of disease conditions in a more stable and long-term manner. Part of the reason for this is that these influences not only affect signaling pathways to produce an immediate outcome, but they can also impact the expression of various genes in both the short and long term. The science of epigenetics deals with the study of environmental influences that have the power to alter gene-environment interactions and can result in stably inherited patterns of gene expression.

In Section 1 of this book, Chapter 1 sheds light on the meaning of epigenetics, its role, and the evolution of its definition.

Section 2 examines the various roles of epigenetics as well as advancements in the field. Chapter 2 examines the Evolution of the Epigenome as the blueprint for Carcinogenesis. Chapter 3 discusses the role of epigenetics, in particular DNA, in different aspects of diabetes. Chapter 4 presents the mechanism of diet–epigenome interactions and how dietary components could be used as "epidrugs" to reverse some epigenetic signatures for positive health outcomes in cancer prevention. Finally, Chapter 5 addresses the effect of social and environmental influences on health and wellbeing at the epigenetic level.

Research in neurobiology was plagued for the longest time by a lack of techniques to "turn on" or "turn off" essential genes and pathways in one cell or one part of the brain to pinpoint a function, a change in neuron firing, or change in a certain signaling pathway. The science of optogenetics, with its single-cell resolution, has made it possible to turn genes on and off in particular cells under the influence of light. This has allowed neurobiologists to improve the assessment of various neurological

functions and disorders. Section 3 of this book provides some Background and Mechanisms Governing Optogenetics Chapter 6 provides information on the meaning of Cyanobacterial phytochromes in Optogenetics.

Chapter 7 discusses the Functional mechanism of proton pump-type rhodopsins found in various microorganisms as a potentially effective tool in optogenetics, and Chapter 8 discusses spatiotemporal regulation of cell-cell adhesions.

Embodying the latest research-based knowledge in epigenetics and optogenetics, this book fosters a deeper understanding of these two disciplines. It presents scientific data and information in an easy-to-follow manner to allow readers from various disciplines of biological sciences, especially undergraduate and graduate students, to develop a better understanding of epigenetics and optogenetics.
