Unrooted phylogenetic tree of the human ORs.The tree was generated by ClustalX program using 347 hOR protein sequences. Positions of olfactory receptors residing on chromosome 11 (green) and 1 (red) are highlighted. The scale bar corresponds to the graphical distance equivalent to 10 % sequence divergence.
Zozulya et al. Genome Biology 2001 2:research0018.1 doi:10.1186/gb-2001-2-6-research0018