This was the first paper to describe cdc mutants. The authors also coined the term 'execution point' — the stage in the cell cycle when the gene function is required. In this paper, three cdc genes were described, which paved the way for the identification of many more such genes, and for the discovery of the molecules and mechanisms controlling the cell

Order of authorship in the original publication: Hartwell, Culotti, Reid. Digital facsimile from PubMedCentral at this link .

In 2001 Hartwell shared the Nobel Prize in Physiology or Medicine with Tim Hunt and Sir Paul M. Nurse "for their discoveries of key regulators of the cell cycle." See also No. 13933.

In this paper the authors demonstrated a "synthetic model of the cell cycle. Genetics had divided the cycle into two parallel pathways, which comprised two sets of dependent steps and involved a total of 19 cdc genes. At the beginning of the cell cycle, both pathways depend on the completion of a step that Hartwell et al. termed 'start'. This event is defined by the famous cdc28 mutant (famous because the cdc28 gene was later shown to encode the founding member of the cyclin-dependent kinase family), and is also the event at which yeast mating factor arrests cell division to prepare cells for mating. With amazing prescience, the authors speculated that 'start' would turn out to be an important control point for the cell cycle in many eukaryotes" (Patterson, Mark. Nature Reviews Genetics, web focus on cell division, Milestone 5, accessed 7-22).

Order of authorship in the original publication: Hartwell, Culotti, Pringle, Reid.