The proliferation of reports on the primary DNA sequences introduces the problem of digesting such information. We consider a condensed characterization of primary sequences of DMA based on 4 X 4 matrices the row and columns of which are associated with the four nucleic bases A, G, C and T. The condensed matrices for the primary sequences of DNA can serve as a source of sequence invariants that would allow quantitative comparisons of DNA from different sources. The approach is outlined on a particular human beta-globin sequence extract.