BACKGROUND: DFR (different region) analysis has been developed for typing Yesinia pestis in our previous study. and in this study. we extended this method by using 23 DFRs to investigate 909 Chinese Y. pestis strains for validating DFR-based genotyping method and better understanding adaptive microevolution of Y. https://www.gulfcoastpetsuppliers.shop/product-category/treats/