Evolution of functions of sperm W chromosome

点击翻译按钮获取中文摘要

We demonstrated that injection of aromatase inhibitor, Fadrozole, (AI) at day 3-5 days of incubation caused sex reversal from female to male chickens. Normal males produce only sperm carrying the Z chromosome (Z sperm), but the sex -reversed hens produce sperm carrying the Z chromosome and W chromosome (W sperm). The presence of W sperm in testes was demonstrated by Southern blot analysis and fluorescence in situ hybridization (FISH). We found that approximately 60% of spermatids were those carrying W chromosome and that about 50% of spermatozoa contained the W chromozome out of 35 spermatozoa examined. To confirm whether the W sperm is functional and fertilizes the oocyte, we conducted intracytoplasmic chicken sperm injection (ICSI) into the hamster ovum. A single sperm was injected into a single hamster ovum. Total of 48 ova injected were incubated at 37 C for 24 hours. According to microscopic observation, 44 (92%) ova were viable and 30 oocytes showed two pronuclei, indicating that injected sperm are capable if inducing at least the early events in zygote formation. These novel findings might ultimately lead to the development of a procedure that produces exclusively female offspring.