Hox Genes:Let's Work Together

Hox genes determine antero-posterior (A-P) axis in all the Bilaterians. Function of Hox genes in a collinear and nonoverlapping order sets the A-P body axis. Hox genes achieve the non-overlapping functions by posterior prevalence phenomenon. In the posterior prevalence a posterior Hox gene dominates over the anterior Hox genes to impose its function in regions of overlapping expression. Now, a few studies have shown exceptions to this rule. This review discusses the mechanisms and exceptions to the rule of posterior prevalence. Our current understanding suggests that anterior and posterior Hox genes have adopted mechanisms to work together during development.