Lost in Redundancy： Dysfunctional Sperm Found Victim of Failed Histone Replacement Caused by Mutant Human Piwi

Male infertility, an issue that has aroused global concern in an era marked with ageing ,population and low birthrate, to a large extent results from decreased quantity and worsened quality of sperm, according to experts. An extreme case is idiopathic azoospermia, a medical condition featuring no sperm in semen. This remains an obstinate disease that has perplexed scientists, as its underlying mechanisms are far from clear and hence no well- targeted treatment strategy is available, let alone any effective therapy or medicine.