<p>An evidence describes the source of an annotation, e.g. an experiment that has been published in the scientific literature, an orthologous protein, a record from another database, etc.</p>
The nucleus is the most obvious organelle in any eukaryotic cell. It is a membrane-bound organelle surrounded by double membranes which contains most of the cell's genetic material. It communicates with the surrounding cytosol via numerous nuclear pores.