Since the 1950s, “Africanized” honeybees have spread north and south across the Americas until apparently coming to a halt in California and northern Argentina. Now genome sequencing of hundreds of bees from the northern and southern limits shows a gradual decline in African ancestry across hundreds of miles, rather than an abrupt shift.
Click here for original story, Genome sequencing shows climate barrier to spread of Africanized bees
Source: Phys.org