The existence of fractal sets of DNA sequences have long been suspected on the 
basis of statistical analyses of genome data. In this article we identify for 
the first time explicitly the GA-sequences as a class of fractal genomic 
sequences that are easy to recognize and to extract, and are scattered densely 
throughout the chromosomes of a large number of genomes from different species 
and kingdoms including the human genome. Their existence and their fractality 
may have significant consequences for our understanding of the origin and 
evolution of genomes. Furthermore, as universal and natural markers they may be 
used to chart and explore the non-coding regions.