Evolution of functions of sperm W chromosome

我们证明，注射芳香化酶抑制剂，法倔唑，（AI）在第3-5天的孵化引起性逆转从女性到男性的鸡。正常的雄性只产生带有Z染色体的精子（Z精子），但是性别逆转的母鸡产生带有Z染色体和W染色体的精子（W精子）。用Southern印迹杂交和荧光原位杂交（FISH）证实睾丸中存在W精子。我们发现大约60%的精子细胞是携带W染色体的，在35个精子中，大约50%的精子含有W染色体。为了确认W精子是否具有功能并使卵母细胞受精，我们将鸡卵胞浆内单精子注射（ICSI）到仓鼠卵中。一个精子被注入一个仓鼠卵子。将总共48个注射的卵在37 ℃下孵育24小时。显微镜下观察，44个（92%）卵子存活，30个卵母细胞显示两个原核，表明注入的精子至少能够诱导受精卵形成的早期事件。这些新的发现可能最终导致开发出一种只产生雌性后代的程序。

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.