Semantides

Semantides are macromolecules common to all cells, used in phylogeny because they change slowly over time. The term was coined by Linus Pauling and Emile Zuckerkandl. Examples of these molecules are:

• rRNA/rDNA
• RNase P RNA
• ATPase
• RecA protein (involved in genetic recombination)
• Cytochrome C
• Heat shock protein genes

The above semantides can yield different phylogenetic trees, but if the genetic relatedness is correct for 2 or more, that correlation could mean that the evolutionary tree is correct.