Uplift and formation of a mountain range divide a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of

Sympatric speciation

Explanation:

Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.