Synteny block

A Synteny block is a set or group of genes ordered next to one another, located linearly on a chromosome. Often the genes found within a particular block encode for proteins of a similar function or purpose within the organism. Synteny blocks have been used in comparative genetics and refer to particular sections of chromosomes' belonging to organisms of a different species that show shared synteny. 

Along with their relevance in comparative genetics synteny blocks have been useful for evolutionary genetics too in regards to their evolutionary history. Thery have been found to be useful for genome evolution, ancestral genome reconstruction, gene family evolution and origin of gene family duplicates^[1]. Patterns of shared synteny are used to give an indication into the phylogenetic relationship between different species and also used to allow geneticists to map the genome organisation of a species over time and observe the changes that have taken place. 

The size of a synteny block and the synteny it shows can be referred to quantitatively where a marcosynteny block indicates the conservation and similarity between large portions of chromosome between different species and a microsynteny block only shows small sections of chromosomal similarity, perhaps only several genes