The sister group of organism A is B. The sister group of the clade B+A, is C.
References[change | change source]
- Eernisse, D.J.. "Introduction to phylogeny: what is a sister taxon?". Biology 404 - Evolution. Department of Biological Science, California State University, Fullerton. http://biology.fullerton.edu/biol404/phylo/sisters.html. Retrieved 4 January 2012.