18S ribosomal RNA

Similar to the prokaryotic 16S rRNA, the genes of the 18S ribosomal RNA have been widely used for phylogenetic studies and biodiversity screening of eukaryotes.

Primers binding in highly conserved regions of the 18S rRNA are an important marker for biodiversity screening,[1] allowing the amplification of unspecified or random targets from environmental samples as well as uncharacterized specimens from collections for DNA sequencing.

[citation needed] In the case of 18S rRNA, retrieval of DNA is improved by the abundance of repeating sequences of the rDNA within eukaryotic cells,[1] promoting the sensitivity of the analysis.

Multiple properties of the genomic sequence of the 18S rRNS have established it as an important marker gene for large-scale phylogenetic analysis and the reconstruction of the metazoan tree of life.

Meanwhile, the gene maintains a high degree of conservation under a persistent selective pressure in all living beings,[1] highlighting its potential for comparison between distantly related clades.