The Evolution of Introns in Human Genes

Introns, which constitute the largest fraction of most eukaryotic genes and which had been considered to be neutral sequences, are increasingly acknowledged as functionally important parts of our genomes. For quite some time, research on levels of nucleotide substitution in human introns has been incomplete and yielded contradictory results, but the finishing of the chimpanzee genome allowed for new and more detailed studies that are proving to be key to unveil intronic functions. Keywords: introns; substitution rates; human–chimpanzee divergence; gene regulation