mutamento poligenetico | - | -
A monogenepolygenetic change is a change that can occur independently in different times and portions of a system, as opposed to the concept of monogenetic change. The picture illustrates the emergence of the same change independently in two different branches of a tree.
As it provides no information on the diffusion of a given innovation, it lacks diagnostic value in the study of contact and inheritance of features.
In the development of writing systems, the application to some degree of the so-called acrophonic principle (logograms receiving syllabic value based on the onset of the words they write) is attested in several contexts that are certainly unrelated. Therefore, when acrophony occurs in different writing systems within a relatively contiguous area, it does not represent a sufficient element for assuming that contact triggered a convergent development (although other hints, such as temporal contiguity or similar fine-grained processes, if present may contribute to suggest that it did).