The stereographical examination of surface spread chromosomes revealed that stretched chromosomes were composed of a mass of twisted looping fibers with an average diameter of about 300 A.

• 在染色质纤维未完全展开排列紧密时，染色体臂的染色质纤维，缠绕排列有序，垂直于染色体纵轴，螺旋盘绕形成疏密程度不同的横纹。