Whether Duplicate Genes Simply Carry Out Redundant Functions In The Genome?

There are a lot of duplicated genes in most eukaryotic genome.Ribosomal protein genes is a typical representative in Saccharomyces cerevisiae. There are 59 pairs copy gene and 19 single copy genes in 137 ribosomal protein genes.This subject is trying to explore the eukaryotes unique ribosomal protein RPL36 two duplicated genes, the RPL36A and RPL36B, duplicate genes to find out whether the gens has special function and meaning in functional and physical.First we’ll check the wild-type FY251 △ 36A, the △ 36B’s ability on cell growth and adaptation to different stress conditions.The Experimental results show that these two different types of missing has very different effect on cell growth.Missing RPL36A will lead to cell growth compared with wild-type slightly slower, while lack of RPL36B will make the cell growth extremely slow.If we duplicated genes deleted on chromosome, via plasmid was transformed into the deletion mutant.I.e. △ A+A, △ A+B, △ B+ B.△ B+A and the endogenous gene RPL36 knock All except via the plasmid was transformed into a RPL36A or RPL36B for genes, i.e.36A (△ 36) 36B (△ 36). and we found the the RPL36A gene on the plasmid is almost exactly the same as the functions of genes and RPL36B.This result reveals that the chromatin structure may affect the repeat gene expression and function of the difference.Then we change RPL36A and RPL36B genes on the chromosome location to get A B interchangeable strains; In the △ 36B strain.we change RPL36A gene to RPL36B gene on the chromosome position to get A ’(only one RPL36A in the chromosome and it is position in RPL36B); In the △ 36A strain.we change RPL36B gene to RPL36A gene on the chromosome position to get B’ (only one RPL36A in the chromosome and it is position in RPL36B):In the wild type FY251 strains. RPL36B gene will replaced by the RPL36A gene, RPL36A gene makes the cells containing without the RPL36B gene, called 2A. the RPL36A gene replacement into RPL36B gene:using this similar method to make the cells contain two RPL36B genes, it call 2B, By spotting assay to check the growth of these strains in a variety of stress conditions, and the use of different types of translation reporter gene to examine these strains for different types of mRNAs translation preference, the results shows that with the same genetic make-up, but the ribosomal protein RPL36A or RPL36B of gene in different chromosomal location strains have different behavior. These results suggest that duplicated genes may not be repeated on the simple functions.After that we want to know the end is the RPL36A or RPL36B gene that part of the chromatin structure may be involved in the decision of these traits. RPL36A gene, its promoter replacement yeast ADH1 promoter; or the same with RPL36B gene to be mutated into different amino acids in the coding region and RPL36B as; or delete the intron; or from intron replace the part as well as 3 "UTR region sequence of RPL36B gene, and carried out to the spotting assay check the growth conditions in different stress conditions. We also RPL36B is handled similarly. The results showed the the promoter part replacement seems to be a more visible effect. In order to check the linkages between RPL36A and RPL36B two duplicated genes, on the basis of these changes RPL36A or RPL36B of gene, entire RPL36B gene knockout (including promoter to the 3’UTR region), or simply RPL36B the coding region of the gene is replaced by the EGFP, but the retained RPL36B promoter to a 11bp region of the second exon and 3’UTR. The results showed that the mutant strains reserved RPL36B promoter than the complete absence of strains of RPL36B gene on the growth and stress response of some drugs is significantly different. These results indicate that duplicate genes have close ties with each other and coordinate their expression and function.In order to more clearly understand some strains of the dynamic response of a particular drug, we made measurements of the the dosing liquid medium growth curve. Such as wild-type FY251 and △ A+A. there is no difference in genotype, but there is an obvious difference in drug sensitivity exhibit, other strains have similar effect.Through the research, we believe that the duplicated genes have not only the compensation function. Every copy has its own specific function and meaning, which also provide evidence for "ribosome code "hypothesis.