摘 要:为研究藏羚羊初生性别比例, 判断母羊怀孕期间有无偏性选择孕育过程, 根据藏羚羊繁殖特点, 在可可西里自然保护区卓乃湖藏羚羊产羔地收集到116份藏羚羊胎盘样品, 阿尔金山兔子湖产羔地收集到32份胎盘样品, 参照文献中对牛科动物进行性别鉴定的3对特异性引物, 利用分子生物学方法对样品性染色体类型进行鉴定, 从而得到藏羚羊新生羊羔的性别, 即藏羚羊初生性比。结果显示, 148份藏羚羊胎盘样品中共有雌性76头, 雄性72头, 初生性比为1︰1.06, 经χ2检验, 差异不显著(P=0.742), 说明藏羚羊初生性比未明显偏离理论值1︰1。以上研究表明, 雌性藏羚羊在怀孕期间无偏性选择作用或这种选择作用非常微弱, 不足以影响藏羚羊种群性别比例; 而且, 利用胎盘对藏羚羊进行初生性比研究是可行的, 其他有类似繁殖模式的野生动物也可用此方法研究其初生性比。

Abstract: To investigate the offspring sex ratio of Tibetan antelope and determine whether sex-biased selection was existent, 116 Tibetan antelope placentas from Zhuonai Lake lambing region in Kekexili Nature Reserve and 32 placentas from Tuzi Lake lambing region in Arjin Mountain National Nature Reserve were collected, which was based on the reproductive characteristics. Then three pairs of bovine sex-specific primers were selected based upon references, and DNA-based sexing was used to determine the sex chromosome type of the placenta samples, by which the sex of the newborns and the sex ratio among them were identified. The results showed that there were 76 females and 72 males among the total 148 placenta samples. The offspring sex ratio was 1︰1.06, with P=0.742 by chi-square test, which meant that no significant sex bias was existent, and that the offspring sex ratio of Tibetan antelope didn’t deviate from the theoretical value of 1︰1. The above-mentioned studies show that, there is no sex-biased selection during the female pregnancy period, or the selective effects may be too weak to affect the sex ratio. It is feasible to study the offspring sex ratio of Tibetan antelope by placenta samples, and this method could also be used for some other wild animals which have the similar reproductive model with Tibetan antelope.