Exactly What is a Gene?

Yesterday, I told you about my tinkering with one gene in an attempt to study it's mRNA product.

But what is a gene???

Simply put, a gene is a segment in your DNA that encodes for a protein (or at the very least a type of RNA product). The entire collection of genes in one organism is called a genome.

Remember the Central Dogma of Biology: DNA => RNA => Protein.

When a gene is "turned on" RNA polymerase is recruited to a stretch of DNA the preceeds the coding region and can then copy the DNA into RNA (i.e. transcription). This recruitment region, called the promoter, doesn't code for protein, it is simply there to start the transcription process. Other regions flanking the genes can recruit factors that influence whether the gene is turned on or off. These DNA regions afre usually called enhancer regions or enhancer elements.

So a gene is the whole thing. The coding regions of the DNA (which gets copied into pre-mRNA), the promoter, and the enhancer elements.