【作者】 王云；

【导师】 刘少军；

【作者基本信息】 湖南师范大学 ， 发育生物学， 2006， 硕士

【摘要】 雌核发育二倍体鲫鲤产生二倍体卵子是一种很独特而又很重要的生物学现象。异源四倍体鲫鲤拥有4套染色体并能产生二倍体卵子,且产生的二倍体卵子在无需加倍处理的情况下,经灭活精子的诱导便可发育成雌核发育二倍体鱼,并可以在不加倍处理的情况下进一步进行雌核发育传代培育。本文对雌核发育鲫鲤第三代的早期胚胎发育进行了观察,并采用RAPD技术,进一步对雌核发育鲫鲤第二、三代的遗传多样性、遗传纯度进行了研究。 1 雌核发育鲫鲤早期胚胎发育的观察 雌核发育二倍体鲫鲤第二代（G₂）产生的二倍体卵子经紫外线灭活的散鳞镜鲤精子诱导,无需染色体加倍处理,发育成为雌核发育鲫鲤第三代（G₃）,其胚胎发育有着与异源四倍体鲫鲤相似的正常的时空发育程序,并能大量形成可存活的雌核发育后代。G₂产生的卵子为粘性卵,色素含量高,共产生3种类型的卵子:（1）直径为1.35mm的小型卵子约占2.47%,与红鲫产生的单倍体卵子大小相近,为单倍体卵子;（2）直径为1.74mm的中型卵子约占95.64%,与异源四倍体鲤鲫产生的二倍体卵子大小一致,为二倍体卵子;（3）直径为1.93mm的大型卵子约占1.89%,可能为更高倍性的卵子。在（19±1）℃水温下,受精后70min第一次卵裂,原肠晚期统计过原肠的百分率为50%,约89h后,受精卵开始脱膜,约106.5h后,胚体完全脱膜,最终统计更多还原

【Abstract】 The diploid gynogenetic hybrids producing diploid eggs is a characteristic and an importance phenomenon of biology. The allotetraploids possesse 4 sets of chromosomes, and produced the diploid gametes. Without the treatment for doubling the chromosome number, the diploid eggs, produced by the allotetraploids, developed into the first-generation diploid gynogen （G₁） following activation by ultraviolet irradiating sperm. Interestingly, like the diploid F₂ hybrids, the G₁ also produced diploid eggs. Furthermore, the second-generation diploid gynogen （G₂） and the third-generation diploid gynogen （G₃） were produced with the same method of producing G₁. In the present paper, the early embryonic development of G₃ was observed, the genetic diversity and genetic purity in the G₂ and G₃ were analyzed by using random amplified polymorphic DNA （RAPD） assay.1 Observation on early embryonic development of gynogenetic progeny from alloteraploid hybridsFollowing activation by UV-irradiated sperm from scatter scale common carp and without the treatment for dubling the chromosome number, the eggs generated by G₂, developed into normal living G₃. The process of the early embryonic development of G₃ was similar to theprocess of the allotetraploid hybrids. The eggs of G2 were stick, the pigment of the eggs was high. The G2 produced three types of eggs, the one was haploid egg, its diameter was 1.35mm, its proportion was 2.47%, the other was diploid eggs, its diameter was 1.74mm, its proportion was 95.64%, the last was polyploid eggs, its diameter was 1,93mm, its proportion was 1.89%. At the water temperature of （19+ 1）°C, the eggs began the first cleavage at 70 min after fertilization and hatched out at 106.5 hours after fertilization. The passing gastrula and hatching rate of eggs was 50% and 26.11%. This study proved that the diploid eggs generated from the diploid gynogenetic hybrids were able to develop into the living progeny without the treatment for doubling the chromosome number. 2 RAPD analysis between G2 and G3The genetic diversity and genetic purity in the G2 and G3 were analyzed by using RAPD assay. Of 300 10-nucleotide-long random primers used in the preliminary analysis, 48 primers produced well-amplified and reproducible band patterns. They were selected and used in the further analysis in 8 of G2 and 8 of G3. The number of loci detected was 406 in G2 and 389 in G3. 6366 （ 3272 in G2 and 3094 in G3 ） distinguishable fragments were compiled for phylogenetic relationship analysis, the average fragments were 8.52 in G2 and 8.06 in G3. The number of polymorphic loci was 41 in G2 and 32 in G3. The percentage of polymorphic loci （10.10%） in G2 was considerately higher than that （8.23%） of in G3. The average genetic distances estimated by Lynchps index was 0.0224 in G2and 0.0201 in G3and 0.0358 between G2 and G3. Two primers, such as S129> S236, were observed to produce specific bands, and these bands could be used as molecular markers for discriminating the G2 from the G3. This study proved that through the gynogenesis, the G3 had higher genetic homozygosis than that of G2.更多还原