AUTHOR CONTRIBUTION
Jingjing Xia and Liang Chang designed the work; Jingjing Xia, Yuqing Jia, Dashuang Xu, Zhaoyu Geng and Sihua Jin collected samples and contributed genetic data; Jingjing Xia, Liang Chang, Yuanfei Ding and Chengcheng Cao contributed data analysis; Jingjing Xia and Liang Chang drafted the manuscript. All authors critically revised and approved the final manuscript.