The first stage of mitosis, during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the cell.

• 前期阶细胞减数分裂的第一个阶段，其间染色体浓缩且能被看见，核细胞膜衰弱，纺锤体在细胞的相对纺锤极形成