clad·o·gen·e·sis 
(klăd′ə-jĕnĭ-sĭs)
(klăd′ə-jĕnĭ-sĭs)n.
An evolutionary process that involves the splitting off or branching of new taxa from an ancestral form.
[Greek klados, branch + -GENESIS.]
clad′o·ge·netic (-jə-nĕtĭk) adj.
clad′o·ge·neti·cal·ly adv.