What is "synteny"

n. (context genetics of multiple genes English) The condition of being located on the same chromosome or region of genome.

In classical genetics, synteny describes the physical co-localization of genetic loci on the same chromosome within an individual or species. Today, however, biologists usually refer to synteny as the conservation of blocks of order within two sets of chromosomes that are being compared with each other. This concept can also be referred to as shared synteny.

The classical concept is related to genetic linkage: Linkage between two loci is established by the observation of lower-than-expected recombination frequencies between them. In contrast, any loci on the same chromosome are by definition syntenic, even if their recombination frequency cannot be distinguished from unlinked loci by practical experiments. Thus, in theory, all linked loci are syntenic, but not all syntenic loci are necessarily linked. Similarly, in genomics, the genetic loci on a chromosome are syntenic regardless of whether this relationship can be established by experimental methods such as DNA sequencing/assembly, genome walking, physical localization or hap-mapping.

Students of genetics employ the term synteny to describe the situation in which two genetic loci have been assigned to the same chromosome but still may be separated by a large enough distance in map units that genetic linkage has not been demonstrated.

Synteny in lay terms is the condition of possessing common chromosome sequences. Many human diseases caused by genetic predisposition have synteny with other mammals and the degree of overlap is indicative of how well a treatment for one will affect the other.

The Encyclopædia Britannica gives the following description of synteny: