  Han Chinese experienced substantial population migrations and admixture in
history, yet little is known about the evolutionary process of Chinese
dialects. Here, we used phylogenetic approaches and admixture inference to
explicitly decompose the underlying structure of the diversity of Chinese
dialects, based on the total phoneme inventories of 140 dialect samples from
seven traditional dialect groups: Mandarin, Wu, Xiang, Gan, Hakka, Min and Yue.
We found a north-south gradient of phonemic differences in Chinese dialects
induced from historical population migrations. We also quantified extensive
horizontal language transfers among these dialects, corresponding to the
complicated socio-genetic history in China. We finally identified that the
middle latitude dialects of Xiang, Gan and Hakka were formed by admixture with
other four dialects. Accordingly, the middle-latitude areas in China were a
linguistic melting pot of northern and southern Han populations. Our study
provides a detailed phylogenetic and historical context against family-tree
model in China.
