That might make sense for an introduced species: it could be the result of a single introduction, or rather of two introductions, one for each supercolony.
"This means that they all probably descended from a single introduction," he told BBC News.
"The idea that it was a single introduction from Chile just doesn't stand up," he says.
A: We still believe it was caused by a single introduction of the virus into the human population.
Consistent with a recent report (Faria et al., 2016), our results also suggested a single introduction of ZIKV into South America (Fig. 1C).
That tree revealed that the children's viruses formed a tight-knit family as would be expected if they stemmed from a single introduction of HIV to the hospital, which was then passed to many different patients.
All viruses from Indonesia in 2005 form a distinct sublineage suggesting their outbreaks are likely originated from a single introduction that spread throughout the country.
In light of the observed patterns of genetic variation in Japan, it seems most likely that the Japanese invasion derives from a single introduction from a hybrid population in the native range.
Generally speaking, a single introduction from a hybrid source appears to be the most parsimonious explanation for the Japanese invasion, and is broadly consistent with both the observed genetic pattens and known invasion history.
In contrast, Bagley and Geller [27] later used limited nuclear microsatellite data to infer that the Japanese population arose as the consequence of a single introduction from a native source population possessing both C. maenas and C. aestuarii mitochondrial haplotypes.
A single synapomorphic SNP has been found for North American Y. pestis, supporting the hypothesis that North American plague is the result of a single introduction [Vogler et al, unpublished data].
