Gene Expression Essay Example | Topics and Well Written Essays - 2000 words

Gene Expression - Essay Example Before we start to Compare and contrast transgenic methods for manipulating gene expression between Drosophila and vertebrate animals let us discuss in brief about what is gene expression and function of genes Gene expression Genes exert their effects on the phenotype. The biological information is contained in the base sequence of DNA. Gene expression is the process by which this information is made available to the cell. This has been described by the central dogma. This states that information is transferred from DNA to RNA and RNA to a protein. During expression gene synthesis from mRNA molecule, into which information has been transferred in the form of genetic code. This synthesis of mRNA from of the strands of the DNA molecule is called transcription. The first step in gene expression is called transcription. Two strands of DNA separate, only one them act as template for the transcription into mRNA in 5’ïÆ'  3’ direction. This strand is non coding (antisense) strand and the other stand of DNA is coding strand (sense strand). This synthesis of polypeptide chain or a protein from mRNA is called translation.... Many genes express whenever the product is required and the expression is regulated. These genes are called regulated genes. Certain genes are expressed as a function of the interaction between RNA polymerase with promoter without any regulation. Such genes are called constitutive genes. They are constantly needed for cellular activities. Flow of genetic information from DNA to protein through RNA was described by crick as central dogma of molecular biology. The studies of bacterial genetics indicate that all genes not only specify the structure of an enzyme but some of them also regulate the expression of other genes. These genes are called regulator genes. This concept of gene regulation has been studied by Franois Jacob and Jacques monod in 1961.the relationship between the nucleotide sequence of mRNA and amino acid sequence that constitute a polypeptide chain is called as genetic code. Gene expression in Drosophila melanogaster Introduction Heterochromatin was originally defined visually as the heavily staining region seen in both the meiotic and interphase nucleus (hietz 1928). The contrast between the openness of euchromantin and the compactness of the heterochromatic implied that the euchromatic is the location of most gene function and led to the neglect of heterochromatin. However, it has become increasingly clear that the nuclear genome is more than a collection of autonomous DNA sequence and that a deeper knowledge of the structure of the nucleus and the chromatin, including the heterochromatin, will contribute to our understanding of the gene expression. In Drosophila melanogaster heterochromatin accounts for approximately 30 % of the genome. Its properties have been studied since the advent