When the program was begun, DNA analysis was performed on the zoo's sika deer, and they discovered that the deer's genetic variation was still very high. At least the herd members were different enough to be acceptable, and the repopulation process was started.
當時曾針對動物園梅花鹿進行 DNA 分析，結果發現動物園的鹿只遺傳變異仍然很高，至少族群歧異度可以被接受，才開始進行復育。