The fifth lecture dealt with the links between epigenetics and the environment, a rapidly developing subject. Examples of epigenetic phenomena linked to a change of season (e.g. vernalization in plants) or nutrition (queen or worker status in bees) were presented. In mammals, the situation is much less clear-cut. It's certain that our environment modifies the expression of our genes, and that this can sometimes lead to stable changes in our traits - and even, in some cases, to the onset of disease. But to what extent can these changes be transmitted from one generation to the next? In recent years, it has been discovered that certain traits are inherited in ways that are not based on changes in the DNA sequence. How important is the role of the environment in this epigenetic inheritance? "Heredity is nothing but a memory of the environment", said Luther Burbank. This question is far from being resolved, despite a number of announcements that have led to a surprising revival of interest in Lamarck's thesis on the heritability of acquired traits - in other words, the idea that traits acquired during an individual's lifetime, as a result of changes in the environment, can be passed on to subsequent generations. This subject was developed in the last lecture.
16:00 - 17:30
