This final lecture takes up several of the points covered in the first four lectures, concentrating mainly on mobile elements, describing the different families of these elements, their evolution and their functions in physiology and pathology. SINEs (Alu) and LINEs, two families of mobile elements involved in the evolution of large primates, are mainly described. It is proposed that SINEs have played a major evolutionary role, and that their accumulation along our lineage over the last seven million years has contributed to the distance between hominins and their chimpanzee and bonobo cousins. LINEs also play an essential role here, not from a quantitative point of view, but through their evolution and the appearance of new subfamilies, in particular the Ta family. LINEs are also essential for SINE activation. In short, the focus on mobile elements is justified when it comes to comparing different groups of human and non-human primates. A final aspect is the neurophysiological role of mobile elements. Indeed, sequences (45% of the genome) that are often truncated provide RNA and regulatory sites but, when intact, also encode active mobile elements. As a result, 3,000 LINEs can still jump from one region of the genome to another in mice, compared with around a hundred in sapiens. These transpositions induce insertional mutations and, what's more, strongly modify genome structure and expression. This can occur both in the germ line, with hereditary effects, and in somatic cells, with physiological consequences. Where there's physiology, there's pathology, and the lecture looked at various neurological and psychiatric pathologies of the nervous system linked to abnormal expression of these elements.
17:00 - 18:30
