Need an argumentative essay on Gene Expression. Needs to be 8 pages. Please no plagiarism.Download file to see previous pages... Before we start to Compare and contrast transgenic methods for manipula

Need an argumentative essay on Gene Expression. Needs to be 8 pages. Please no plagiarism.

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’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.