Hybrid zones are useful in studying the genetics of speciation as they can provide natural examples of differentiation and gene flow between populations that are at some point on the continuum between diverging populations and separate species with reproductive isolation.

hybrid zone is a tension zone maintained by dispersal and ecologically mediated barriers to gene flow. KEY WORDS: AFLP, cline, hybridization, ecological selection, environmental gradient, gene flow, migratory divide, tension zone.

In this study, the ability to compare hybrid zone dynamics from contemporary and historical samples (separated by 40 years) provided a means of testing hypotheses about the evolution of a hybrid zone, and also provided additional support (stable location and width of the hybrid zone) for the classification of the grosbeak hybrid zone as a ...

The area in which two closely-related species interact and reproduce is known as the hybrid zone; their offspring are known as hybrids. Depending on the fitness of the hybrid offspring relative to the parents, the two species may either stay as two distinct species (reinforcement), or become one species again ( reconnection ).

At the western and eastern edges of the hybrid zone, nearly all birds sampled look like typical Bullock’s Orioles and Baltimore Orioles, respectively. But in the mid­dle, orioles display a spectrum of possible plumages—mixing many combinations of Bullock’s and Baltimore colors and patterns.