Recently I went through a paper about hepatocellular carcinoma in which they talked about trunk genes (p. 26, second paragraph):
Branching tumor evolution complicates efforts to implement personalized medicine and suggests that targeted therapies might be directed to genes that are mutated at the trunk of the evolutionary tree. Transposons provide powerful tools for identifying trunk genes, as insertions in trunk genes are more likely to be associated with a higher number of sequencing reads.
I really don’t understand what are the trunk genes. Can anyone please explain them clearly.