鲫鲤F₁和F₂自交受精细胞学及异源四倍体的起源

【作者】 曹运长；

【导师】 刘筠；

【作者基本信息】 湖南师范大学 ， 动物学， 2001， 硕士

【摘要】 本文运用组织细胞学方法分别对鲫鲤杂种F₁代自交F₂代及F₂代自交F₃代的受精细胞学进行了研究。 F₁代、F₂代的成熟卵为端黄卵，F₁代成熟卵直径为1.0-1.25mm，F₂代成熟卵直径有三种：1.3mm、1.7mm、2.0mm。F₁代、F₂代的成熟卵都为单受精孔卵，一般只允许单个精子入卵，成熟卵在受精之前处于第二次减数分裂中期，F₁代、F₂代雌、雄部分可育，其受精方式为单精受精。 在水温18-21℃下，F₁代精子进入F₁代卵子5分钟后出现明显的精子星光，同时，卵子排出第二极体；15分钟后，雌、雄原核形成；25分钟后，雌、雄原核融合为合子核；40分钟后，开始第一次卵裂，在一个受精卵的切片上看到了一个三极纺锤体；以后每隔20分钟进行一次卵裂。在同样的水温下，F₂代的精子进入F₂代的卵子18分钟后出现精子星光，同时卵子排出第二极体；28分钟后，雌、雄原核均已形成；53分钟后，雌、雄原核融合为合子核；65分钟后，开始第一次卵裂；以后每次分裂间隔时间大约为15分钟。 综上所述，鲫鲤杂种F₁代自交F₂代及F₂代自交F₃代具有正常的受精细胞学程序。由此得出结论：F₂代二倍体精子（大头精子）与F₂代二倍体卵子（直径1.7mm）受精产生异源四倍体（F₃代），同时，对F₂代中二倍体配子的产生及F₃代异源四倍体能保持稳定遗传的原因进行了初步的探讨。更多还原

【Abstract】 This paper presents the studies of cytological behavior of autocopulation fertilization of F1 F2 hybrids of Red crucian( ) X Common carp() by means of light-inicroscope.The results are generalized as follows:The diameter of mature oocytes of F1 hybrid is between 1.0-1.25mm,which that of F2 hybrid is roughly divided into three types:1.3mm, 1.7mm,2.0nim.The mature eggs of F1,F2 hybrids stay at the metaphase of secondary maturation division before fertilization,with a micropyle through which usually only single sperm is allowed to penetrate.Normal spenn is available from the male and female F1 F2 hybrids which are partially fertile . F1,F2 hybrids comply with the pattern of monospermism,also with the normal process of fertilization.Firstly,the study on autocopulation fertilization of FI hybrid was conducted.ln the surroundings of 18-20C of the water temperature,the spennaster was appeared obviously and the elimination of the second polar body was accomplished at 5~15 minutes after fertilization.By the 15 minutespostinsemination,the male and female pronuclei were formed,and subsequently,they moved toward the center of blastodisc,then contacted with each other,lastly fused completely to be the zygotic nucleus.The first cleavage occurred at about 40 minutes after fertilization,when a tripolar spindle was found in a section of one zygote.Secondly, the study on autocopulation of F2 hybrid also was perfonned.In the same condition of water temperature,the appearance, of spcrmaster and the extrusion of the second polar body were observed at 18 minutes after insemination,By 28 minutes postinsemination,the formation of male and female pronuclei were found.At 53 minutes after feitilization,the male and female pronuclei were merged,then first segmentation occurred at 65 minutes postinsemination.the interval between the successive divisions is about 15~20minutes.All in all,the autocopulation fertilization of F1, F2 hybrids agrees with the general fertilization laws,it is concluded that allotetraploid fish (F3) was produced by the fertilization between diploid spermatozoa and diploid eggs produced by F2. In addition, the present paper discusses the reason why diploid gametes in F2 was produced, and why the allotetraploids can produced next generations steadily in gene and phenotype.更多还原