In the current context of environmental changes, it is easy to see how extrinsic factors, such as shifts in sea surface temperature, food availability and accumulation of pollutants, can impact the health of marine mammals. However, intrinsic factors, including the genetic constitution of an individual, are also largely responsible for shaping health, particularly in terms of immune system effectiveness. In the previous edition of this book, the chapter on genetics thoroughly addressed the techniques available for identification of species, populations, stocks and individuals, studying social organization, and determining the relationships among individuals in a group. We have written the current chapter with an emphasis on how each individual’s genetic constitution and the prevalence of particular genetic variants is relevant to marine mammal health and disease. The chapter first presents a brief conceptual framework for understanding how genetics shape health and disease. We next outline common genetic techniques and current tools and technologies that are emerging in marine mammal health studies. Finally, the scope, pitfalls and limitations of these tools are discussed.
