Author contributions
W. G. and G. H. supervised and designed the research. WZ. L. conducted
field investigation and sample collection. WZ. L., JG. X. and H. Z.
carried out the lab work. WZ. L., HH. K., W. G., and PW. F. analyzed the
genomic data. WZ. L., PW. F. and W. G. discussed the results and wrote
the manuscript. All authors read and agree with the manuscript.