Conservation is a high degree of similarity in the primary or higher structure of homologous proteins amongst various phyla. A highly conserved protein is often related to an important cellular function. A mutation in a highly conserved region leads to a non-viable life form, or a form that is eliminated through natural selection. Highly conserved proteins are often required for basic cellular function, stability or reproduction.
In eukaryotes, highly conserved genes are often located more toward the centromeres of chromosomes.