Before revision:  With the right balance, incorrect attachments are resolved spontaneously into correct bioriented conformations . Our work revealed that a probabilistic URLanization, rather than a sophisticated process of error detection and correction , is responsible for the biorientation of kinetochore-microtubule attachments .
After revision:  With the right balance, incorrect attachments are resolved spontaneously into correct bi-oriented conformations while an imbalance leads to persistent errors. In addition, the model explains why errors are more commonly found in the first meiotic division (meiosis I) than in mitosis and how a faulty conformation can evade the spindle assembly checkpoint, which may lead to a chromosome loss. Conclusions: The proposed model, despite its simplicity, helps us understand one of the primary causes of chromosomal instability - aberrant kinetochore-microtubule interactions. The model reveals that chromosome bi-orientation is a probabilistic URLanization, rather than a sophisticated process of error detection and correction , is responsible for the biorientation of kinetochore-microtubule attachments .