Genetic DNA Identification from Bone Remains in Kinship Analysis Using Automate Extraction System

*Raluca Dumache,Talida Cut, Camelia Muresan, Veronica Ciocan, Emanuela Stan, Dorin Novacescu and Alexandra Enache*

#### **Abstract**

The first ever human identification through DNA analysis was done in the year 1987. Since then, this test has been used, not only in the ruling of civil and juridical cases, but also for human identification of missing persons and mass disaster victims. In this chapter we will present the usefulness of genetic DNA testing of skeletonized remains for human identification, by using automate DNA extraction from three different human bone types: tooth, femur and petrous pyramid. For each case, we obtained saliva samples on buccal swabs from relatives. After the bones were washed and cleaned, Bead Balls Mill Mix 20 (Tehtnica Domel, Slovenia), was used to obtain the bone powder. The DNA extraction from bone samples was performed on the automate Maxwell RSC 48 Instrument (Promega, USA), using the Maxwell FSC DNA IQ Casework Kit (Promega, USA). Power Quant System (Promega, USA) was used for DNA quantification of the samples. The DNA samples were amplified on a Pro Flex PCR System (Thermo Fischer, USA), using the Global Filer PCR Amplification Kit (Applied Biosystems, USA). PCR products were run on a 3500 Genetic Analyzer (Thermo Fischer, USA). Data analysis was performed by Gene Mapper 1.4. Considering that these cases involved DNA extraction from teeth, bones and old human remains, automate system was felt to be the best option to reduce handling errors and increase the possibilities of obtaining good quality DNA.

**Keywords:** deoxyribonucleic acid (DNA), human identification, postmortem, bone remains, International Society of Forensic Genetics (ISFG)

#### **1. Introduction**

During the last three decades, the field of forensic genetics that applies genetic science for human identification has experienced new changes and advances in molecular sciences, owing to recent discoveries in the field of molecular biology. With respect to human DNA identification, establishing kinship between individuals is based on Mendel's laws, which stipulate that individual inherit genetic traits from their biological parents in equal contribution. Thus, an individual's genetic DNA profile contains all the ancestor's DNA and is unique, excepting the case of monozygotic twins. Genetic identification using autosomal short tandem repeat (STR) markers is based on this principle. Genetic human identification can also be done on DNA haploid markers, which are the markers found on X-chromosomes and Y-chromosomes. These markers are inherent in maternal or paternal lines and are used in cases where one of the biological parents is dead [1].

In forensic genetics, short tandem repeats (STR) are the genetic markers used for human identification in cases of kinship determination, paternity or maternity rulings, crimes, sexual assaults, and burglaries. DNA samples obtained from different items can be tested to prove the presence or absence of a person in a crime scene, thus serving an important purpose in the criminal justice system [2]. Obtaining DNA profiles from bone remains and teeth is an important procedure that helps in human identification in cases of mass disasters or unidentified human remains. Human remains are the only biological samples that remain after destructive events, after exposure to harmful environmental conditions or in cases where a long time has passed since the death of the person [3]. DNA molecules degrade gradually in hard tissues, such as bones and teeth, which makes them available for DNA extraction for longer periods of time [4]. Many external factors such as humidity, temperature, pH, geochemical properties of the soil, presence or absence of micro-organisms, storage time and conditions, and various other factors can affect the preservation of DNA molecules in skeletal remains [5, 6].

It is known that after death of the organism, DNA damage and bone fragmentation can occur, thus it is especially important to understand the composition of bone and teeth and their decomposing process. The root of the tooth is covered with cementum, a biochemical structure containing hydroxyapatite, collagen, and other non-collagenous proteins. On the other side, dental pulp represents an important source for DNA extraction. According to international recommend It is known that after death of the organism, DNA damage and bone fragmentation can occur, thus it is especially important to understand the composition of bone and teeth and their decomposing process. The root of the tooth is covered with cementum, a biochemical structure containing hydroxyapatite, collagen, and other non-collagenous proteins [7]. On the other side, dental pulp represents an important source for DNA extraction. According to international recommendations the most suitable teeth are molars, premolars, and canines.

Regarding the bones, compact bone tissue makes the outer part of the ends of long bones (epiphysis) and flat bones and the middle part of the long bones (diaphysis). The spongy part of the bones is found inside the flat bones and at the ends of the long bones. Because over time the porosity of the bones will increase, bacteria and fungi who are present on soils, and cyanobacteria present in water will penetrate more easily inside the bone tissue [8].

Based on the current recommendations for sampling forensic bone remains, long leg bones (femur and tibia) and teeth are the most suitable for DNA extraction, while spongy and flat bones such as skull, ribs and vertebrae are less suitable.

In such cases, the possibility of isolating DNA from hard tissue serves to benefit forensic science [9]. After bone cleaning and DNA isolation from biological samples, laboratory protocols require the following steps to be taken to perform human identification on DNA samples: DNA quantification, amplification of DNA products using polymerase chain reaction (PCR) and visualization of the PCR products using capillary electrophoresis.

In this chapter, we will show the advantages of DNA human identification from bone remains, the concentration of which will differ depending on the type of the

*Genetic DNA Identification from Bone Remains in Kinship Analysis Using Automate… DOI: http://dx.doi.org/10.5772/intechopen.99587*

bone being tested. We will present three cases of human DNA identification, performed on three different types of human bones.
