The cellular mechanisms and consequences of centromere drive.

During female meiosis, only one of four meiotic products is retained in the egg. It was previously proposed that chromosomes might compete for inclusion in the egg via their centromere 'strength'. Recent findings have revealed the primary requirements for such 'centromere drive'. First, CDC42 signaling from the oocyte cortex renders the meiotic I spindle asymmetric. Second, 'stronger' centromeres preferentially detach from microtubules in cortical proximity, making them more likely to orient away from the cortex, and be included in the egg. Third, centromeric satellite DNA expansions result in greater recruitment of centromeric proteins. Despite these mechanistic insights, it is still unclear if centromere drive elicits rapid evolution of centromeric proteins, thereby driving cellular incompatibilities and wreaking havoc on centromere stability.