Sentence:  The computer programs used to generate “trees” from genetic distance data will do so regardless of what evolutionary factors generated the distances. It is therefore the obligation of the users of such programs to ensure that the genetic distance data have the properties of <WSD>treeness</WSD> before representing their data as a tree. 
Meaning of the word marked with <WSD> tags:  The suitability of an evolutionary tree for representing the structure of a population; the degree to which a population structure can be accurately described as a tree of descent, with different branches evolving independently after they split.