A method to ascertain a possible gene doping case it could be by monitoring the mRNA expression of a candidate gene with non invasive image techniques. In order to solve this matter, we require specific marked sequences to track them by image techniques and they have to selectively hybridate with the target mRNA. The peptide nucleic acids (PNAs) have all this characteristics, as well as they are stable enough in the cell cytoplasm. The PNAs are artificial molecules that are analogous to natural nucleic acids (DNA and RNA). The ribose-phosphate framework of nucleic acids has been replaced with repeated units of N-(2-aminoethil)glycine linked with amide bonds, similar to peptides and proteins. Due to these physico-chemical characteristics, PNAs hybridate with complementary DNA in a more stable and specific way than the equivalent hybridation DNA-DNA. An hypothesis to consider is that ¹⁸F or ¹²³I marked PNAs, once injected, must make possible to detect the presence of an specific mRNA in a tissue through molecular image techniques.

The goal of this project is the search of unique subsequences in the human genome of the Growth Hormone (GH), the Insulin-like Growth Factor-1 (IGF-1) and the Erythropoietin (EPO) genes, as well as unique sequences of the mouse Erythropoietin (EPO) gene in its genome. As a result, this subsequences would be the basis to synthesize the complementary and specific PNAs to detect if the mRNA of this genes (GH, IGF-1 and EPO) is present in a tissue.

Nevertheless, the execution time of the unique subsequences' search of that genes in the human genome, by means of a program written in Perl and the Knuth-Morris-Pratt algorithm, can take 40 days for each gene in a conventional computer at best. Faced with the impossibility of finding this patterns due to lack of time or "computational power", the initial goals of that project have been modified to reproduce the results for the mouse EPO gene obtained previously by Dr. Robert Castelo (with a program with the brute-force algorithm written in C language). That is, the definitive goal of the project is to corroborate that the three unique patterns found in the mouse EPO gene are unique subsequences of mouse chromosome 5, where that gene is located, and that the program works properly and it can find the unique subsequences for the desired mRNA and genome in an appropriated time limit.