Gene expression

From EvoWiki

1 Introduction
2 Transcription
3 Translation
4 Gene regulation
5 Footnotes
6 References

[edit] Introduction

Gene expression is the process by which a gene is translated into a polypeptide and the function that that polypeptide performs - that is, the way in which a phenotype is arrived at.

Gene expression consists of a number of complicated biochemical pathways. All genes must undergo transcription into an RNA molecule, and most genes are then translated into a polypeptide¹. Many of these polypeptides act as enzymes, becoming part of the machinery for further biochemical pathways, specific to each enzyme.

[edit] Transcription

In transcription the DNA molecule unwinds and the double helix separates. An enzyme then produces an RNA copy of the gene, called messenger RNA (mRNA). The mRNA carries the code for the polypeptide chain to the molecular machinery which will build the polypeptide.

... Continue reading on the Transcription page.

[edit] Translation

In translation the base sequence of mRNA is converted into a sequence of amino acids, the monomers (building blocks) of the polypeptide. Translation occurs on a piece of molecular machinery called a ribosome. The RNA alphabet is translated into the amino acid alphabet following the rules of the genetic code.

... Continue reading on the Translation page.

[edit] Gene regulation

When, and in which cells and tissues a gene is expressed, and how much polypeptide is produced, must be very strictly regulated. There is a very complex system of chemical signals involved in the regulation of gene expression, the mechanisms of which are not fully understood yet.

... Continue reading on the Gene regulation page.