Genes of a multicellular organism are heterogeneous in the G+C content, which is 
particularly true in the third codon position. The extent of deviation from 
intra-strand equality rule of A = T and G = C (Parity Rule 2, or PR2) is 
specific for individual amino acids and has been expressed as the PR2-bias 
fingerprint. Previous results suggested that the PR2-bias fingerprints tend to 
be similar among the genes of an organism, and the fingerprint of the organism 
is specific for different taxa, reflecting phylogenetic relationships of 
organisms. In this study, using coding sequences of a large number of human 
genes, we examined the intragenomic heterogeneity of their PR2-bias fingerprints 
in relation to the G+C content of the third codon position (P3). Result shows 
that the PR2-bias fingerprint is similar in the wide range of the G+C content at 
the third codon position (0.30-0.80). This range covers approximately 89% of the 
genes, and further analysis of the high G+C range (0.80-1.00), where genes with 
normal PR2-bias fingerprints and those with anomalous fingerprints are mixed, 
shows that the total of 95% of genes have the similar finger prints. The result 
indicates that the PR2-bias fingerprint is a unique property of an organism and 
represents the overall characteristics of the genome. Combined with the previous 
results that the evolutionary change of the PR2-bias fingerprint is a slow 
process, PR2-bias fingerprints may be used for the phylogenetic analyses to 
supplement and augment the conventional methods that use the differences of the 
sequences of orthologous proteins and nucleic acids. Potential advantages and 
disadvantages of the PR2-bias fingerprint analysis are discussed.