The conservation of chromosomal segments containing groups of homologous genes in the same order and orientation among different species. Chromosomal regions containing such genes are termed syntenic blocks, and identifying them in related species is helpful in determining whether similar genes are truly orthologous or not. Syntenic blocks can contain from a few up to several thousand genes, and syntenic maps have been compiled to show how these blocks are distributed between the chromosomes of different species. For example, the long arm of mouse chromosome 1 contains a large region that it shares with human chromosome 2. Hence, similar genes localized to these regions are likely to share a common ancestor.
Subjects: Biological Sciences.