The Y has been described as a wimpy degraded relic of the X, with imminent demise should it lose sex-determining function. Why then has it persisted in almost all mammals? Here we present a novel mechanistic explanation for its evolutionary perseverance: the persistent Y hypothesis. The Y chromosome bears genes that act as their own judge, jury, and executioner in the tightly regulated meiotic surveillance pathways. These executioners are crucial for successful meiosis, yet need to be silenced during the meiotic sex chromosome inactivation window, otherwise germ cells die. Only rare transposition events to the X, where they remain subject to obligate meiotic silencing, are heritable, posing strong evolutionary constraint for the Y chromosome to persist.

Y被描述为X的弱化降解遗物，如果失去了决定性别的功能，则即将灭亡。为什么它在几乎所有哺乳动物中都持续存在？在这里，我们为它的进化恒久性提供了新颖的机械解释：持久性Y假设。Y染色体带有在严格调控的减数分裂监测途径中充当其自己的判断，陪审团和execution子手的基因。这些execution子手对于成功的减数分裂至关重要，但在减数分裂性染色体失活窗口期间必须保持沉默，否则生殖细胞会死亡。只有向X发生的罕见转座事件才是可遗传的，在X处发生了专一的减数分裂沉默，这对Y染色体的持久形成了强大的进化约束。