Phenotypes such as germline stem cell number and hub size showed much less or no significant difference between the Set1 KD and Ctrl KD testes, respectively (Fig. 1E,F), whereas the cyst cell number continued to increase in the Set1 KD testes compared with the Ctrl KD testes from L3 to day 7 (Fig. 1G). Here, SETD1A is linked to cyst.