Chromosomal mapping, differential origin and evolution of the <it>S100 </it>gene family
2008
Zhou Rongjia | Cheng Hanhua | Shang Xuan
<p>Abstract</p> <p>S100 proteins are calcium-binding proteins, which exist only in vertebrates and which constitute a large protein family. The origin and evolution of the S100 family in vertebrate lineages remain a challenge. Here, we examined the synteny conservation of mammalian <it>S100A </it>genes by analysing the sequence of available vertebrate <it>S100 </it>genes in databases. Five <it>S100A </it>gene members, unknown previously, were identified by chromosome mapping analysis. Mammalian <it>S100A </it>genes are duplicated and clustered on a single chromosome while two <it>S100A </it>gene clusters are found on separate chromosomes in teleost fish, suggesting that <it>S100A </it>genes existed in fish before the fish-specific genome duplication took place. During speciation, tandem gene duplication events within the cluster of <it>S100A </it>genes of a given chromosome have probably led to the multiple members of the <it>S100A </it>gene family. These duplicated genes have been retained in the genome either by neofunctionalisation and/or subfunctionalisation or have evolved into non-coding sequences. However in vertebrate genomes, other <it>S100 </it>genes are also present <it>i.e. S100P</it>, <it>S100B</it>, <it>S100G </it>and <it>S100Z</it>, which exist as single copy genes distributed on different chromosomes, suggesting that they could have evolved from an ancestor different to that of the <it>S100A </it>genes.</p>
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