In this edition we publish the first of our new series of Yeast ‘Primer’ articles. Since its inception, Yeast has published research on molecular aspects of yeast biology, with an emphasis on the popular model yeasts, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe. In recent years, as genome sequences multiply, many more yeast species have become amenable to molecular approaches, and increasingly this has been reflected in the papers we publish.