Genetics For Dummies, 3rd Edition

Chapter 11

Gene Expression: What a Cute Pair of Genes

IN THIS CHAPTER

Defining gene expression

Confining gene activities to the right places

Controlling genes before and after transcription

Every cell in your body (with very few exceptions) carries the entire set of genetic instructions that make everything about you. Your eye cells contain the genes for growing hair. Your nerve cells contain the genes that turn on cell division — yet your nerve cells don’t divide (under normal conditions). So why, then, aren’t your eyeballs hairy?

It boils down to gene expression. Gene expression is basically the transcription and translation of a gene – the production of the protein that is encoded by the gene. Genes that are supposed to be active in certain cells are turned on only when needed and then turned off again, like turning off the light in a room when you leave. This process is highly regulated; your cells need to make sure the right genes make their products at the right time and in the right place. This chapter examines how your genes work and what controls them. Most of the chapter will focus on gene expression in eukaryotes (organisms with cell nuclei), with only a brief discussion ...