The fucosyltransferase gene family: an amazing summary of the underlying mechanisms of gene evolution.

The fucosyltransferase gene family encodes enzymes that transfer fucose in alpha 1,2, alpha 1,3/4 and alpha 1,6 linkages on a large variety of glycans. The most ancient genes harbour a split coding sequence, and encode enzyme that transfer fucose at or near O- and N-peptidic sites (serine, threonine or chitobiose unit). Conversely, the more recent genes have a monoexonic coding sequence, and encode enzymes that transfer fucose at the glycan periphery. All basic mechanisms of gene evolution contribute to this amazing scenario: exon shuffling, transposition, point mutations, and duplication. As typical examples: (i) exon shuffling leads to the ancestral organization of the alpha 1,6 fucosyltransferase gene; (ii) the ancestor of alpha 1,2 fucosyltransferase genes is reshaped by retrotransposition at the same locus; (iii) duplication associated to point mutations leads to the most recent alpha 1,3/4 fucosyltransferase genes.