DNA analysis is widely applied in solving forensic cases, especially Short Tandem Repat (STR) because of its advantages. In identifying the individual, the National Police compared the individual's DNA with that of his parents. Each anal has a pair of DNA fragments of which half are inherited by the father and the remainder by the mother according to Mendel's Law of Segregation. In this study, we compared DNA typing between the child and the mother with the help of PCR extracted by the Chelex method to find the mother fragment and obtain the father fragment. A child is the biological child of the alleged father if he or she has less than 2 exclusion STR loci. The results of this study revealed that all paternal fragments from the child were identical to the DNA fragments of the alleged father, except for one locus, namely CSF1PO which had a mutation. Mutations in the STR locus lower the paternity index, although it can still be concluded that the child is the biological child of the alleged father.   Keywords: Paternity Test, DNA, STR, Mutation

Analysis of Touch DNA on forensic laboratory has been a favorite approach to identify a person. Every investigator demand the identity of whom the perpetrator that commit the crime, that leaved their DNA on the evidence. Many factors affect touch DNA, one of these is the substrate of the evidence. Common evidences that often examined in forensic lab are firearms, knife, swords, clothes, and switch bomb. To collect the cell on the evidence we use tapelift method using the duct tape. PrepFilerTM BTA Extraction Kit used to extract the DNA from the duct tape, followed by Quantifiler® Duo. For profiling the DNA we use GlobalFilerTM and fragment analyzed on ABI 3500 Genetic Analyzer followed by GeneMapper ID.X. V.1.4. Based on our analysis, DNA from fabric substrate has the higher percentage of success DNA profiling. The success DNA profiling rate of fabric and plastic substrate is 100%, and 0% for wood substrate. According to recent researches, smooth substrate, like plastic and glass, has higher percentage to get full profile than rough substrate, like woods. But on the fabric, they found has much higher percentage than smooth substrate. This can be due to the absorption ability of the fabric to obtain more cells

In some crimes, blood spots are found in water, either in bathroom tubs, ponds, bathing tubs for clothes, rivers, etc. Spots of blood in the water are also not uncommon to be found splashed on clothes or other objects. This study aims to determine the effect of water media on DNA testing from mixed blood. The results of this study are expected to provide an overview for forensic DNA examiners in cases related to evidence of blood in water or blood in water splashed on clothes or other things. The samples used were fresh blood taken from 3 donors (2 women and 1 man) who were treated with 1:5000, 1:4000, 1:3000 and 1:1000 dilutions as well as detergent and touch treatments. Presumptive test was carried out first on blood spots on clothes, DNA analysis was carried out by DNA extraction, DNA quantification with Real time PCR, amplification of STR loci and fragment analysis. Based on the results of this study, it is known that water affects DNA quality. Both direct examination of water media and blood in water that has moved to clothes. Likewise, blood that has been exposed to detergent cannot be subjected to further DNA analysis. ABSTRAK Dalam beberapa tindak pidana bercak darah ditemukan di dalam air baik di bak kamar mandi, kolam, bak rendaman pakaian, sungai, dsb. Bercak darah dalam air ini juga tidak jarang ditemukan memercik pada pakaian atau benda lain. Penelitian ini bertujuan untuk mengetahui pengaruh media air terhadap pemeriksaan DNA dari darah campuran. Hasil dari penelitian ini diharapkan dapat memberi gambaran pada pemeriksa DNA forensik dalam kasus yang berhubungan dengan barang bukti darah dalam air atau darah dalam air yang terciprat pada pakaian atau beda lain. Sampel yang digunakan adalah darah segar yang diambil dari 3 donor (2 perempuan dan 1 pria) yang diberi perlakuan pengenceran 1:5000, 1:4000, 1:3000 dan 1:1000 serta perlakuan detergen dan sentuhan. Uji presumptive dilakukan terlebih dahulu pada bercak darah di pakaian, analisis DNA dilakukan dengan ekstraksi DNA, kuantifikasi DNA dengan Real time PCR, amplifikasi lokus STR dan analisis fragmen.  Berdaasarkan hasil penelitian ini diketahui bahwa air mempengaruhi kualitas DNA. Baik pemeriksaan secara langsung dari media air maupun yang darah dalam air yang telah berpindah ke pakaian. Begitu juga darah yang telah terpapar dengan detergent tidak dapat dilakukan analisis DNA lebih lanjut.