1939年,Darlington重新解释等臂染色体(isochromosome)由着丝粒横断所致,染色体的两臂相等,在遗传学上为同源。在植物和昆虫,由于着丝粒断裂方式不规则,等臂染色体是不稳定的;而在人类,这种遗传上的失调是很致命的,它的本质尚不清楚。在肿瘤病人的骨髓细胞中出现等臂染色体,作为获得性异常却常有报道。尚不清楚为什么等臂染色体好发于特定的 In 1939, Darlington reinterpreted that the isochromosome was caused by a centromere transection. The two arms of the chromosome were equal and genetically homologous. In plants and insects, since the centromere breaks are irregular, the arm chromosome is unstable; in humans, this genetic disorder is fatal and its nature is not yet clear. The presence of ischemic chromosomes in the bone marrow cells of tumor patients has been reported as an acquired abnormality. It is unclear why the arm chromosomes occur in specific