Evolution of functions of sperm W chromosome

我们证明，在孵化第3-5天注射芳香酶抑制剂法洛唑(Fadrozole，AI)可引起母鸡到公鸡的性别逆转。正常雄性只产生携带Z染色体的精子(Z精子)，但性反转的母鸡产生携带Z染色体和W染色体的精子(W精子)。Southern印迹分析和荧光原位杂交(FISH)证实W精子在睾丸中的存在。我们发现，大约60%的精子细胞是携带W染色体的，在所检测的35个精子中，约有50%的精子含有W染色体。为了确定W精子是否具有功能并使卵母细胞受精，我们对仓鼠卵子进行了卵胞浆内鸡单精子注射(ICSI)。将单个精子注射到单个仓鼠卵子中。共注射48枚卵子，37℃孵育24小时。镜下观察，44个卵(92%)有活力，30个卵母细胞有两个原核，说明至少能诱导早期合子形成的精子是有能力的。这些新颖的发现可能最终导致一种只产生女性后代的程序的开发。

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.