Evolutionary Emergence of Genes Through Retrotransposition

Variation in the number of genes among species indicates that new genes are continuously generated over evolutionary times. Evidence is accumulating that transposable elements, including retrotransposons (which account for about 90%of all transposable elements inserted in primate genomes), are potentmediators of newgene origination. Retrotransposons have fostered genetic innovation during human and primate evolution through: (i) alteration of structure and/or expression of pre-existing genes following their insertion, (ii) recruitment (or domestication) of their coding sequence by the host genome and (iii) their ability to mediate gene duplication via ectopic recombination, sequence transduction and gene retrotransposition.