The field of human mitochondrial genetics has advanced way beyond where the Human Genome Project hopes to be by the year 2003, the projected year for completing the sequence of the entire human nuclear DNA genome. Not only has the mitochondrial DNA (mtDNA) been completely sequenced, the regions that code for genes and those that are noncoding have been distinguished, the function of all the genes have been determined, the mtDNA genetic code has been shown to differ in some ways from the Universal Genetic Code of nuclear DNA, and a number of diseases have been correlated with specific mitochondrial DNA mutations (http//infinity.gen.emory.edu/mitomap.html).Some of the current areas of research interest with regard to mitochondrial genetics are: examining the variability among individuals or within a single individual (heteroplasmy), distinguishing between polymorphisms and disease-producing mutations, detecting mutations present in low concentrations in an individual, analyzing the effects of chemical or physical agents and the mechanisms which lead to mutations or biochemical defects, understanding the progressive nature of mitochondrial diseases, determining evolutionary relationships among human populations and phylogenetic relationships among species, correlating mitochondrial changes with the aging process, and understanding the role of mitochondria in the regulation of apoptosis (programmed cell death)(Green and Reed, 1998). All of these areas of scientific inquiry will provide important forensic, medical, phylogenetic or evolutionary information and all of them depend upon the determination of sequence differences.Several molecular methodologies have been successfully applied to the examination of mitochondrial polmorphisms and mutations. Although sequencing an entire region of DNA provides the most comprehensive genetic information, a number of screening assays have been developed for detecting single base pair changes [e.g., single nucleotide polymorphisms (SNPs) and deleterious point mutations], deletions, insertions, and duplications. One of the avenues for providing researchers with necessary controls or calibration tools for use in the analysis of human DNA is the development of Standard Reference Materials (SRMs) by the National Institute of Standards and Technology (NIST). Use of these SRMs can help assure that the data being collected, published, and entered into massive databanks or on the Internet are correct. This chapter will review some of these current areas of scientific interest with regard to human mitochondrial genetics.
Biotechnology & Genetic Engineering Reviews
diseases, DNA, forensics, genetics, heteroplasmy, human, mitochondria, standard reference materials