Sister group

closest relative(s) of another given taxon in a phylogenetic tree

A sister group or sister taxon is a term used to describe the closest relatives of an organism (or other taxon) in a phylogenetic tree.[1] It is a term in cladistics.




The sister group of organism A is B. The sister group of the clade B+A, is C.


  1. Eernisse, D.J. "Introduction to phylogeny: what is a sister taxon?". Biology 404 - Evolution. Department of Biological Science, California State University, Fullerton. Retrieved 4 January 2012.