Abstract: This invention provides modified nucleotide sequences encoding luciferase that have greater expression than wild type luciferase.

Abstract: The present invention provides compositions, kits, assemblies, libraries, arrays, and high throughput methods for large scale structural and functional characterization of gene expression regulatory elements in a genome of an organism, especially in a human genome, that are part of a common pathway. In one aspect of the invention, an array of expression constructs is provided, each of the expression constructs comprising: a nucleic acid segment operably linked with a reporter sequence in an expression vector such that expression of the reporter sequence is under the transcriptional control of the nucleic acid segment. The present invention can have a wide variety of applications such as in personalized medicine, pharmacogenomics, and correlation of polymorphisms with phenotypic traits.