SSU rRNA

Small subunit ribosomal ribonucleic acid (SSU rRNA) is the smaller of the two major RNA components of the ribosome. Associated with a number of ribosomal proteins, the SSU rRNA forms the small subunit of the ribosome. It is encoded by SSU-rDNA.

Use in phylogenetics
SSU rRNA sequences are widely used for determining evolutionary relationships among organisms, since they are of ancient origin and are found in all known forms of life.