polygenesis >> /ˌpɑliˈdʒɛnəsəs/
Definition: [noun] The hypothetical origination of a race or species from a number of independent stocks.
Example: For example, it seems to be the ground of his preference for monogenesis - the theory that the races are descended from a common stock - over polygenesis - the theory that the races have different origins.
Definition: [noun] The hypothetical origination of language or of a surname from a number of independent sources in different places at different times.
Example: Proponents of polygenesis hold that the concept of genetic relatedness between languages is inaccurate.