公骡精母细胞的减数分裂  

SPERMATOCYTE MEIOSIS IN MALE MULE (EQUUS ASINUS×EQUUS CABALLUS)AND HINNY (EQUUS CABALLUS×EQUUS ASINUS)

作　　者：赵振民[1] 支德娟[1] 王敏强[1] 杨博辉[1] 

机构地区：[1]中国农业科学院兰州畜牧与兽药研究所,兰州730050

出　　处：《动物学报》2002年第1期69-74,共6页ACTA ZOOLOGICA SINICA

基　　金：中国农业科学院院长基金项目"动物种间杂种不育多样性及其遗传机理研究"的部分内容 (项目编号 :90 2 7-10 )~~

摘　　要：关于骡不育以及个别母骡偶然生育的现象 ,历来存有争议 ,认为因亲本染色体歧异导致杂种不能进行减数分裂的理论 ,否认骡生育的事实 ;而为母骡生育提出解释的理论则认为一定是母骡产生了只含单一亲本染色体组的卵子 ,回交后代已回归为马或驴。但是一些新的研究却证明 ,事实与上述理论都存在明显矛盾。为了进一步探讨种间杂种生殖隔离现象的遗传机理 ,本研究采用性成熟公骡的睾丸为材料 ,制备组织切片和减数分裂联会复合体标本进行观察 ,发现个别性腺发育较好的个体虽然减数分裂存在大量异常 ,但确有少数精母细胞完成了减数分裂并产生精子。在骡的精母细胞内 ,发现有与马的联会复合体相似的线段状物 ,电镜下可辨其某些片段呈双线性结构。据此结果对杂种不育的传统理论进行了讨论 ,认为应综合考虑杂种的异源染色体和异源细胞核与细胞质相互作用的双重影响 。The sterility of mule (Equus asinus×Equus caballus) and the phenomenon of exceptional female mules giving birth to offspring occasionally have been remaining controversal in academic cycles for a long time. The theory of chromosome diversity of parents which resulted in failure in hybrids meiosis, and denied the fact of reproduction in mules. Another theory explained the fecundity of female mules in the way that the female mule must have produced oocyte containing only a single parental set of chromosome, and the offspring from backcross would be horse (Equus caballus) or donkey (Equus asinus). But some new evidences are contradictory with the two theories mentioned above. For further studying the genetic mechanism of the reproductive isolation phenomenon of interspecific hybrid, paraffin sections of testes from 13 sexually mature male mules (Equus asinus×Equus caballus) and 12 hinnies (Equus caballus×Equus asinus) were prepared, and the samples of Giemsa meiosis and AgNO 3 synaptonemal complexes were observed and compared with spermatocyte meiosis of horse and donkey under light microscope and electronic microscope. We found that there was significant individual difference in the testis development of mule. A few hybrids had better developed testis and meiosis occurred. The amount of spermatocytes in the spermatogenic tube of the testis in hybrids was significantly higher than that in the common mule. There were some spermatocytesⅠ and a few spermatocytesⅡ, but they entered the antrum of tube. There were a lot of aberrant chromosomes including fragmentation, disorder, adherence, arc, annulus, etc. Nevertheless, a few spermatocytes did complete the process of meiosis and form sperm. During the prophase of meiosisⅠ, some chromosomes at the zygoten/diploten stage existed in parallel; at the pachyten stage, chromosomes became broad, but some segments were thin and not paired; at the diploten stage, synaptonemal complexes did not divided in phase, so at the diakinesis, some chromosomes were still in

关 键 词：种间杂种 骡 减数分裂 精母细胞 杂种不育 

分 类 号：Q953.3[生物学—动物学]