Caused by the emergence of Robertsonian rearrangements in intersubspecies hybrid

日本梅花鹿（Cervus nippon）有四种染色体变异。这些染色体变异是由于两个单中心常染色体对的罗伯逊融合，导致形成一个稳中心对。九州型（4号和5号）和后藤型（18号和27号）之间的异中心对的形成涉及不同的外中心对。结合这些类型和杂交的分布格局以及染色体变化的方向，可以推断出：(1)北方型先从亚洲大陆传入日本，然后是Chugoku型；(2)九州型和后藤型是由日本Chugoku型独立分化而来。

Four types of chromosome variations in Sika deer Cervus nippon were recognized in Japan. These chromosome variations were due to the Robertsonian fusion of two acrocentric pairs of autosomes, resulting in the formation of one metacentric pair. Different acrocentric pairs were involved in the formation of a metacentric pair between Kyushu type (nos.4 & 5) and Goto type (nos.18 and 27). Considering the distribution pattern of these types and hybrid and the direction of chromosome changes, it could be inferred that 1) Northern type first and then Chugoku type came into Japan from the Asian continent, and 2) Kyushu type and Goto type were independently differentiated from Chugoku type in Japan.