Abstract: Our research conducted with the genome sequences of more than 250 species of organisms (including viral, microbial, and multi-cellular organisms, and human) results in the discovery that the occurrence of a particular subsequence (the so-called “motifs” or “n-mers,” (n being the length of the subsequences), which can be up to 25 and higher) in the genome of a particular species can be considered as a nearly random event; and that the occurrences of a particular subsequence in the genome sequences of different species can be considered as nearly independent events (with the exception of the cases where extremely closely related species are compared). The set of subsequences that occur in a particular species' genome can therefore be used as a genomic “fingerprint” of this species. This discovery leads to the concept of utilizing a set of pseudo-randomly designed subsequences for species identification or discrimination.