Smelt was the likely beneficiary of an antifreeze gene laterally transferred between fishes

摘要: Type II antifreeze protein (AFP) from the rainbow smelt, Osmerus mordax, is a calcium-dependent C-type lectin homolog, similar to AFPs herring and sea raven. While lectins are ubiquitous, type only found in few species three widely separated branches of teleost fishes. Furthermore, several other non-homologous intervening species. We have previously postulated that this sporadic distribution has resulted lateral gene transfer. The alternative hypothesis, AFP evolved present shared ancestor was lost most species, not favored because both exon intron sequences highly conserved. Here we sequenced annotated 160 kb smelt BAC clone containing centrally-located along with 14 genes. Quantitative PCR indicates there but single copy within genome, which atypical for fish corresponding syntenic region been identified searched number be devoid or sequences. Unlike introns gene, intronic flanking genes conserved between As well, rate pattern mutation radically different those seen These results provide stand-alone support an example transfer vertebrate They should further inform debate about genetically modified organisms by showing ‘higher’ eukaryotes can occur naturally. Analysis regions fishes strongly suggests acquired herring.