Figure 1. Attachment of spindle MTs to kinetochores.

The process by which chromosomes establish connections with MTs emanating from the two spindle poles is a highly stochastic one. Initially, different unstable modes of MT attachment may occur, for instance, syntelic attachment (A) or merotelic attachment (B). In such cases, action of Aurora B/Ipl1p disengages some of the MTs to promote monotelic attachment (C). Following this step, stable attachment is achieved when the sister kinetochore captures MTs originating from the spindle pole at the opposite end (amphitelic/bipolar attachment) (D). In such an arrangement, poleward forces generate tension between sister kinetochores.