Author Contributions
Lin Huang and Yufei Feng made contributions to conception and design.
Yinyu Zhao and Nan Guo helped with the acquisition of data. Boyu Liu and
Lei Hu performed the extraction of genomic DNA and genotyping. Xu Hao
performed the statistical analysis, interpreted the data and wrote the
manuscript. Yinyu Zhao drew the figures and tables. Nan Guo helped to
revise the manuscript. Fang Liu provided guidance on statistical
analysis. Xiaoyan Nie and Feng Yu were involved in revising it
critically for important intellectual content. All authors gave final
approval of the version to be published.