Abstract
One of the main task in forensic laboratories is species identification from tissues or body fluids in order to distinguish human from different animal remains. Using body fluids, particularly blood is on a significant forensic value. Todays, hundreds of blood-based transcriptome from different animal species as well human are publically available. Using data mining approach includes i) dataset collection and quality control assessment, ii) overlapping to identify a set of species specific genes, iii) normalization to GAPDH in order to identify included upregulated genes and iv) overlapping both species specific genes with upregulated ones to identify the most possible genes of forensic values. Among thousands of genes, HLA-C, HLA-E, HLA-F, IGLC1, JAML, MALAT1 and TRBC1 were exclusively identified in human´s blood. However, in rats, horses, cows, pigs, chicken and dogs, 7, 16, 11, 10, 15 and 22 genes were identified, respectively. In rat´s blood, FTL1, GP1BB, HBA1, HBB-B1, LGALS5, RT1-A1 and RT1-A3 were exclusively specific. However, FLJ27505, FLJ35848, GALNACT-2, LYPLA3, OR2M3, OR2T4, OR4A15, OR4F15, OR52A5, OR5T1, OR8U8, PVRL2, RP11-529I10, SLC10A5, TMPRSS7 and TRA16 were identified only in horse´s blood. In cow´s blood, we were able to identified BOLA, CLDN25, CSDA, CYTB, EPB49, HBE4, HRNBP3, OR6S1, PLA2G2D1, RNASEN and RNF160 as specific genes. In pig´s blood, we found that ARPC3, COX3, CYTB, ND1, PTGES, RPS10L, RPS11P5, TCTP, TMSB15A and TWEAK were specifically observed. However, in chicken, BF1, BF2, B-G, BG2, H3F3C, HBAA, HABE, HBG1, HBG2, ISG12-2, MT-CO3, P20K, RPS17L, TDH and URP were exclusively identified. Eventually, in dog´s blood these genes ADAM29, ANKRD5, BET3L, CAFA-T2R55, CEACAM23, cOR2AV2, cOR52X2, DLA-12, DLA-64, DLA-79, Dla88, DLA-DRA, EFCAB4B, EMR2, GPR109A, IFNA6, IGHAC, PGA, PTCD1, PVRL1, SLIT1 and THR were exclusively identified. In conclusion, this datamining approach identifies species-specific genes, which can beused as a marker in forensic labs.

Key words: mRNA, transcriptome, forensic, identification