【作者】 项迎霞；

【导师】 孙野青；

【作者基本信息】 大连海事大学 ， 生物物理学， 2010， 硕士

【摘要】 空间辐射包括电子、质子、重离子等电离辐射。电离辐射能够引起基因组不稳定,即细胞受到辐射后,在被辐射的细胞的多世代中仍出现基因组突变率增加,引起后代延迟突变。基因组不稳定表现为基因突变、微卫星不稳定等。经神舟6号载人飞船飞行搭载后水稻种子于地面连续种植,在第三代中发现紫色突变。将紫色突变植株种植,后代出现紫色和绿色性状分离现象,表明空间飞行能够诱发水稻紫色突变表型不稳定遗传,这种表型的不稳定性可能是基因组的不稳定导致。为探索空间飞行引起水稻基因组不稳定的序列特征和分子机理,本研究利用AFLP技术,对空间环境引起水稻叶色突变植株进行了基因组突变位点扫描,研究多态性位点的序列特征,并检测多态性位点在后代中的遗传或突变情况。实验结果检测到29个多态位点,对其中20个测序后比对水稻基因组序列,发现14个位点(70%)位于水稻基因组非基因区,5个位点(25%)位于基因区,1个位点(5%)与现有水稻基因组序列不匹配,表明空间飞行引起的水稻基因组不稳定主要发生在非基因编码区。检测其中8个突变位点紫色和绿色同源植株的突变序列特征,得到34个点突变、1个微卫星序列异常和4处缺失突变。相同方法检测M4代紫色和绿色植株,发现点突变增至43个,其中10个位点(23.26%)稳定遗传,19个位点(44.19%)与颜色性状共发生。本次研究发现空间飞行能够诱发基因组不稳定,水稻的紫色突变可能是空间引起基因组不稳定的表现；空间飞行引起水稻基因组不稳定主要发生在非基因编码区,主要突变类型为点突变,其他突变类型包括微卫星序列重复数改变和小片段缺失；本次研究为从分子机理解释空间生物学效应表现提供了有价值的数据。更多还原

【Abstract】 Space environment included a variety of ionizing radiation such as electron, proton and heavy-ion. Ionizing radiation can cause genome instability, In principle, this radiation-induced genome instability will contribute to increase mutation rates in multi-generation. Genome instability encompasses a wide range of alterations, including gene mutation, microsatellite instability. Rice seed was growth on ground after space flight by Shenzhou-6 spacecraft. After three generations of continuous cultivation, we found the offspring of 4 individuals in the second generation appeared purple leave. The offsprings of purple mutation was observed both purple leave and green leave. We discovered that the purple rice trait was the performance of genome instability. To find genome sequence characteristics and molecular mechanism of space radiation induced genome instability, AFLP molecular marker technology was used to search for polymorphisms of sequence characteristics of purple rice induced by the space environment.29 polymorphism loci were detected by AFLP. By sequencing 20 polymorphism loci, we found those 14 polymorphism loci on non-coding sequence and 5 polymorphism loci on coding sequence. This result showed that space-flight induced rice genome instability mainly occurs in the non-coding region. To investigate the genome sequence characteristics of the mutation caused by space-flight,8 polymorphism loci were used to study the purple mutation.34 point mutations,1 microsatellite sequence anomalies and 4 deletion mutants were found in purple mutation. To study the genetic of the mutation, we found 43 polymorphism loci on the next generation, including 10 polymorphism loci exhibited genetic stability and 19 polymorphism locic concurrences with purple mutation. These results show that space flight could induce rice genome instability. The point mutation was mainly occurred on non-coding sequence. The purple mutation was the performance of rice genome instability. The purple mutation also exhibited genetic instability. Our findings may also have general implications in the molecular mechanism of space biology.更多还原