Statistical Analysis Of Gene Expression Levels In Yeast Genome

Saccharomyces cerevisiae is the first complete genome sequencing of eukaryotes.Since S.cerevisiae genome is relatively small,simple structure and genetic background is relatively clear,so it has been widely used as a eukaryotic model organism.Now S.cerevisiae have achieved rapid development in gene function analysis,transcriptome,proteome,and many other levels.S.cerevisiae in the study of modern molecular biology and cell biology has played an important role.Taking advantage of the homology of the coding sequence and the structure of the human genome and the genome of model organisms,which not only can provide a good reference model for us to study the higher life,but also provide a good positive reference to the study of the human genome.In this thesis,a gene expression database for S.cerevisiae was established.This database includes mRNA sequences,gene expression data during cell cycle,protein functional classification information,and the classification information of essential genes and nonessential genes.Based on this database,we investigated whether the varied degree of gene expression is related with its sequence features,functional classification and co-expression network.Our study shows:1,Varied degree of gene expression related with gene function,the gene with important function tends to have low fluctuation of gene expression levels during cell cycle.2,The folding stability of mRNA secondary structure is a factor affecting the varied degree of gene expression,the low stability of gene structure contributes to the high fluctuation of gene expression.The low abundance of tRNA can also lead to high fluctuation of gene expression.3,The results of analyzing gene co-expression network suggest that the varied degree of gene expression levels during cell cycle is significantly positively correlated with the number of co-expressed genes.