| The DNA methylation was one most important kind of epigenetics' modification, and it was an important method to adjust function in genome. The research of the DNA methylation and the heterosis relations was at the start stage, so it was unable to determine the direct relation to the different expressing genes changed by DNA methylation and the phenotype changing of F1 generation at present. It had the explicit answer the form of heterosis was or not the result of the action of the different expressing genes, so they had the theoretic and the practical significance uderstanding heterosis the hereditary basis through the gene expression and the heterosis forecasted.Therefore, this research usesd 5 maize inbred lines and using incomplete diallel crossing to obtain 10 hybrid combinations for the material to study, and using Methylation-sensitive amplified polymorphism(MSAP) researching technique, systemic analysising distributed situation of the DNA methylation polymorphism in the different of maize inbred lines and their hybrid; discussing relations in the difference of DNA methylation polymorphism and the heterosis in hybridizing process; screening and excavating related essential gene of heterosis for maize and the variation in methylation position spot; to lay the molecular foundation for deeping research on the apparent heredity mechanism to epigenetics' mechanism of heterosis for maize. The main result of this research was as follow:1.After 44 pairs of the primer's combination was used to carry on the on the selectivity increasing, it was obtained the clear band in 20 pairs of the primer's combination. It was analysised to CCGG position spot's methylation level for combination's parents and hybrid F1 generation. The result indicated that,9 combination's the filial generation's non-methylation rate was higher than parent' in 10 combinations, only 1 combination's the filial generation's non-methylation rate must was lower than parent'; 9 combination's the filial generation's methylation rate was lower than parent', only 1 combination's the filial generation's methylation rate was equal to parent'. It indicated that in the hybrid process, filial generation's methylation level reduced and the non-methylation level elevated. In the experiment, some individual combination parent non-methylation rate was lower than the filial generation, explained that it might be concerned by different variety's combination in the parent inbred line department. To the CCGG methylation level, in 10 combinations, the primary form was the inside cytosine methylation namely entire methylation in parent and filial generation, and filial generation's distribution was lower than the parent in the entire methylation distributed condition of filial and parent generations in 9 combination, filial generation was higher than the parent in 1 combination. But the flank cytosine half methylation respectively was actually dissimilar in the parent and filial generation's distribution, some filial generation was lower than the parent in 6 combination, filial generations was higher than the parent in 3 combination, and filial generation was equal to the parent in 1 combination.2.To statistics to parents and filial generation's methylation pattern types in the 10 combinations, The quantites to amplified the average of sites for methylation was 99.2. The kinds of singlet state was maximum in these sites, that had 78.1 at average and the rates were 78.73. The most kinds of multiformity was demethylation type, that had 13.8 at average in the multiformity sites and the rates were 13.91, but the rates in the rest of multiformity types were less. The extrapolation hybrid F1 filial generation's methylation pattern changed and the gene expression related, thus and the heterosis was related.3. The six agronomic characters were analysed to the heterosis, and it discovered that the high of plant, the high of spike, the long of spike, the thick of spike, the axle diameter, the line of spike, all of the 6 characters were forward direction to the heterosis.4. The got rid of the methylation fragments reclaimed were carried to homologous compared in NCBI Genebank. From finded the homologus in 5 fragments compared, they discovered that the methylation appeared in the entire corn genome team; the methylation was concerned to the corn' many physiological phenomenon and vital activity, mang regions of gene participated in the expression and regulation; But it was further to analysed the relations of the heterosis. |
