Introduction 3. Transformation of sequence of nucleotides in gene-based speckle pattern 3.1. Algorithm of re-coding of a nucleotide sequence 3.2. Algorithm of generating of 2D speckle pattern, based on a nucleotide sequence 3.3. Generating of gene-based speckles 4. Comparison of GB-speckles, based on similar genovars: cross-correlation technique 5. Comparison of GB-speckles, based on similar С. trachomatis genovars of different subtypes: speckle-interferometry 6. Optical processing of GB-speckles: detection of genetic mutations in a gene of microorganisms 7. Conclusions 8. Acknowledgment 9. References