(1) (physiology) The regeneration of tissue.
(2) (evolution) An evolutionary pattern resulting in linear descent and not to divergence or branching to additional species.
In evolution, anagenesis is used to contrast catagenesis. In anagenesis, the theory holds that as the species evolve through time, changes in gene frequency may lead to the formation of new species replacing the old, and not branching to another species.
Word origin: Greek ana– (on, up, above, throughout)
Related form(s): anagenetic (adjective)