Gene Elements Promoter Enhancers Response Grouped Control Gene's

Enhancers are several response elements that are grouped together, which allow for the control of one gene's expression by multiple signals.  

Enhancer regions can be up to 1000 base pairs away from the gene they regulate and can even be located in an intron.  Differ from promoter elements because promoter elements must be within 25 bases of the start of the gene.

Gene Duplication can result in the continuous replication of a gene until hundreds of copies of the gene exist in parallel on the same chromosome