Shrunk, tamed, crossbred and eaten, are bison now a domesticated species?

缩小、养、杂交、被食用，现的野牛能算是种了吗？

DNA analyses in Namibia found the four groups have not crossbred for million of years and therefore evolved into distinct species.

纳米比亚进行的DNA分析发现，这四个品种过去数百年没有杂交，因此进成不同的品种。