The South American weed Mikania micrantha has spread rapidly across Southern China since its introduction to the Shenzhen region in 1984. Geng et al. used SSR markers to investigate and map genetic diversification of this weed along highways.
The results show a relatively low level of genetic differentiation, a lack of clear geographic genetic structure and strong gene flow between populations. The long-distance dispersal of seeds associated with vehicular transportation on highways may have provided corridors for the spread of M. micrantha in Southern China, thereby shaping genetic variation.