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Relative Degradation of Nuclear and Mitochondrial DNA: An Experimental Approach

NCJ Number
215139
Journal
Journal of Forensic Sciences Volume: 51 Issue: 4 Dated: July 2006 Pages: 766-770
Author(s)
David R. Foran Ph.D.
Date Published
July 2006
Length
5 pages
Annotation
In order to compare mitochondrial DNA (mtDNA) and nuclear DNA degradation, mouse tissues (muscle, liver, and brain) degraded at different temperatures, and the relative degradation of a mitochondrial gene, a single-copy nuclear gene, and a multicopy nuclear gene were assayed by the use of real-time polymerase chain reaction (PCR).
Abstract
The experiments conducted show that successful DNA locus recovery from degraded tissues involves many factors. A higher gene copy number, as is the case for both the 28S ribsomal RNA gene and the cytochrome b gene (Cyt b), is a significant factor in obtaining typing results as tissues and DNA decay; however, other factors apparently influence significantly the ability to amplify DNA markers in degraded material, including cellular location and perhaps transcriptional activity. Although a unique cellular location will continue to be the only domain of mtDNA in animals, locus type and gene expression may be features worth considering when selecting nuclear DNA markers for forensic analyses. DNA loci that are down-regulated or unexpressed in tissues or body fluids of forensic interest, including blood, semen, bone, etc., might offer the best choice for analysis from degraded material. Overall, taking into account gene copy number, tissue type, and the function of DNA loci could improve the ability of forensic practitioners to analyze markers in degraded forensic material. The description of materials and methods addresses the materials and conditions for tissue degradation, DNA isolation, real-time PCR, and data analysis. 1 table and 23 references