DNA may get all the credit, but the behind-the-scenes manipulator of genetic information, making DNA perform the myriad functions of life, is epigenetics. Dr. Mykura introduces this exciting field, which is rewriting our understanding of gene expression, and how our behavior and the environment can influence traits that were previously thought to be hardwired into our genetic code.
Delve into the molecular machinery of the epigenetic code, that living jungle which controls our DNA. See how the central dogma of cell biology, that DNA makes RNA makes proteins, is only possible due to epigenetic processes. Also, see how epigenetic factors create a system of inheritance that is entirely separate from—but intimately involved with—our genomes.
Explore the epigenetics of food and how our diet can affect our DNA. A famous example is the Dutch famine at the end of World War II, which left a legacy of health problems not just among the survivors, but also in their yet-to-be-conceived descendants—an outcome that defied traditional genetics. Discover how epigenetics explains this phenomenon, as well as trends such as today’s obesity epidemic.
Epigenetics plays a key role in aging, giving humans long lives compared to other mammals, but also setting a limit on longevity. This raises the question: Can we use our knowledge of epigenetics to stop aging, or at least slow it down? Focus on an enzyme called telomerase, which in theory can restore cells to youth, but at a terrible cost. In this light, consider the advantages of aging.
The brain is the most complex structure that we know, able to produce an infinite variety of behaviors and store prodigious amounts of information. Learn how epigenetics governs the genes that are expressed within the brain. Then, look at brain pathologies such as schizophrenia that are partly due to epigenetic effects. Also, evaluate the impact of drug use on brain development.
See how epigenetic changes due to diet and cigarettes can affect the heart and lungs. For example, lung cancer was once considered a disease of genetic processes, but it is now known to involve many epigenetic mutations that disrupt the on/off state of specific genes. Then study a more positive phenomenon: how the epigenetic alterations from regular exercise can have long-term health benefits.
Follow the ongoing epigenetic battle taking place in all of us. It pits naturally occurring or environmentally induced cellular damage, which could lead to cancer, against the powerful mechanisms of DNA repair. Compare the chromosomes in a healthy cell versus a cancerous cell. Also, look at different cancer triggers, including ultraviolet light and the body’s hormonal and microbial environments.
The body’s immune system incorporates a huge amount of epigenetic complexity. Learn how this works in the two types of immunity: innate and adaptive. Innate immunity is inherited and evolutionarily very ancient, while adaptive immunity can respond to pathogens that may have evolved mere hours ago. Probe the danger of immune cells attacking the body’s own cells in autoimmune diseases.
Why are there two sexes, and what does epigenetics have to do with it? Zero in on the X and Y chromosomes, following events that cause a fertilized egg with two Xs to develop ovaries, while an embryo with an X and a Y develops testes. Investigate why the Y chromosome has a minimal number of genes and whether it will eventually disappear from the sexual reproduction of our species.
Rewind the process of embryogenesis to individual egg and sperm cells. Although their epigenetic features are largely wiped clean, they still must orchestrate the complex development of an embryo to produce a baby. Study the steps needed to get to a fertilized egg and the even more involved epigenetic processes as the embryo differentiates. Also, pinpoint steps where embryogenesis can go wrong.
Does epigenetics mean that 19th-century French biologist Jean-Baptiste Lamarck was right about the inheritance of acquired characteristics? Learn that this phenomenon, called transgenerational epigenetic inheritance, is difficult to prove, especially in humans. In the search for evidence, evaluate a prominent study of isolated human populations. Then, see that plants shed intriguing light on this question.
Turn back the clock to the era before DNA, when RNA may have dominated life processes, playing both genetic and epigenetic roles. Focus on the epigenetics taking place in bacteria, as well as in older, single-celled organisms called archaea. Go deeper into the diverse epigenetic activity in plants. Finish the course by looking ahead at the many promising lines of research in epigenetics.