The genome

The genome (gene content) is all the genes – so all the DNA – in a cell of an individual.

• Many genes carry instructions for making proteins. Others specify the sequence of nucleotides in ribosomal RNA (rRNA), used to build ribosomes, and transfer RNA (tRNA), which carries amino acids in protein synthesis.
• In prokaryotes, the genes for RNA and protein make up most of the genome.
• In eukaryotes, only a small percentage of DNA codes for proteins; the rest is non-coding (not transcribed to make RNA or proteins).