Chapter 20B Mitochondrial DNA in forensic genetics

Abstract

Publisher Summary This chapter describes mitochondrial deoxyribo nucleic acid (DNA) on forensic genetics. Mammalian mitochondrial DNA (mtDNA) is a closed circular molecule that contains 16 569 base pairs (bp). The entire human mitochondrial DNA sequence has been determined functions and gene products have been assigned to all mitochondrial genes, including 13 protein-coding, 2 rRNA, and 22 tRNA genes. The mtDNA is maternally inherited, because of this it does not go through recombination with each generation, representing only the maternal ancestry of an individual. It has the following characteristics: (1) Robustness: the mtDNA is more robust that nuclear DNA. (2) Large amount of molecules per cell, 1000–10,000: there are a large number of copies compared to chromosomal DNA, providing results when genomic DNA does not. (3) Rapid rate of evolution with a 5–10 times higher mutation rate than nuclear DNA. (4) Maternal inheritance, not recombination, giving the possibility to study family members from the same maternal lineage. The mtDNA has become very important in anthropological and evolutionary research and in forensic genetics. Analysis of mtDNA is a valid method to be applied in forensic genetics; however, its study presents some problems that are addressed in this chapter. Problems, such as mutation rate, heteroplasmy, homopolymeric tracts, statistical approach, etc. All of them are important for the reliability of the mtDNA results.