Also encoded by structural genes are non-coding RNAs, such as rRNAs and tRNAs (but excluding any regulatory miRNAs and siRNAs).
The distinction between structural and regulatory genes can be traced back to 1959 and work by Pardee, Jacob, and Monod—the so-called PaJaMo experiment—on the lac operon and the synthesis of proteins in E. coli.
[1] In prokaryotes, structural genes of related function are typically adjacent to one another on a single strand of DNA, forming an operon.
[6] The identification of the genetic basis for the causative agent of a disease can be an important component of understanding its effects and spread.
Location and content of structural genes can elucidate the evolution of virulence,[7] as well as provide necessary information for treatment.
[8] For example, Yersinia pestis (the bubonic plague) was found to carry several virulence and inflammation-related structural genes on plasmids.
[13] Structural genes in general are more highly conserved due to functional constraint, and so can prove useful in examinations of more disparate taxa.
[14] More recent phylogenetic approaches focused on structural genes of known function, conserved to varying degrees.
Recent genetic discoveries call into question the distinction between regulatory and structural genes,[18] suggesting greater complexity.
Structural gene expression is regulated by numerous factors including epigenetics (e.g. methylation) and RNA interference (RNAi).