Clone	A group of cells that are all descended from a single ancestor. Mutations that are shared between these cells are commonly described as ‘clonal’.
Subclone	Cells originating from a more recent cell than the most recent common ancestor. These will possess both the clonal mutations and also subclonal mutations that are private to the subclone.
Driver mutation	A mutation with a beneficial functional impact on a cell (for example, affecting growth, invasion, or metastasis).
Passenger mutation	A mutation with no functional impact. Both driver and passenger mutations (the latter representing the large majority of mutations) can still be used to identify clonal or subclonal populations.
Most recent common ancestor (MRCA)	The theoretical founder cell of the tumor, from which all cancer cells in a cancer sample are derived. The most recent common ancestor possesses all mutations that are common to all of the tumor cells.
Branching evolution	Divergence in tumor evolution leading to separate subclonal populations.
Linear evolution	The absence of apparent divergence or branches in evolution. All evolution prior to the MRCA will always appear linear as all other pre-MRCA branches have become extinct.
Gradual evolution	An iterative pattern of mutation acquisition and selection over time.
Punctuated evolution	Discontinuous acquisition of mutations over time with periods of relative stasis. Mutations may be acquired in distinct patterns and be co-located, or can be distributed across the genome.