More on genetic compexity: exons are the coding portion of genes. Introns are interruption areas in genes, so that genes are not one continuous strip of code. This degree of interruption developed in early evolution and is most prominent in humans. Its development is now being studied in cyanobacteria, one of the earliest forms of bacteria. The interruptions allow for iRNAs to piece together different parts of a gene to create different functions of the gene, allowing the whole gene to do several jobs. This is probably why we have so few genes for so many functions. And this is why we have so many layers of control of this mechanism, as well as review and repair mechanisms to insure accuracy of all processes of copying. See this article:-http://www.physorg.com/news195236809.html