polygenesis

noun4

1. •
   The genesis of a species from more than one ancestor.
2. •
   The theory that living organisms originate in cells or embryos of different kinds, instead of coming from a single cell; as opposed to monogenesis.
3. •
   The theory that languages developed independently in different places at different periods, as opposed to originating from a single source.
4. •
   The emergence from multiple causes or origins.

   • The contrasting theory of polygenesis assumes that resemblances among tales can be attributed to independent invention in places unconnected by trade routes or travel. — 2003