EMBO Workshop — The yin and yang of chromosomal and extra-chromosomal DNA

Eukaryotic cells maintain their genome as linear chromosomes in the nucleus and smaller, circular chromosomes in their autonomous organelles. Sporadically, they also contain non-chromosomal DNA, generally in circular form, due to recombination of chromosomal fragments, movement of DNA from mitochondria to the nucleus, uptake of extracellular DNA, or the presence of selfish DNA of endogenous or exogenous origin, like transposons and viruses. When it does not harm or kill the cell, this material may contribute to the evolution and structural dynamics of the genome. Reversely, selfish DNAs evolve sophisticated machineries to multiply and propagate independently of, but also frequently via chromosomes. During this meeting we will review recent insights on the complex relationships that chromosomes and extra-chromosomal DNAs entertain with each other, discussing how cells distinguish them, how their relationships contribute to the biology of the cell in health and disease, and affect genome plasticity and evolution. The intricate relationships between chromosomes and extra-chromosomal DNAs are raising fundamental questions in both basic and medical sciences. We will further conceptualize these questions and discuss how to best approach them experimentally and theoretically.