Consideration of heteroduplexes and homoduplexes forthe quantification by competitive PCR of humanmitochondrial DNA deletions with ageing of tissues and cells

Abstract

The purpose of this work was first to construct twointernal standards for human mitochondrialDNA mt DNA corresponding respectively to the fragmentresulting from the 4,977 bp common deletion (H2del) and a fragment which was never reported to be deleted(H1). Secondly, we wished to consider thepossible effect of annealing between the target andcorresponding internal standard which forms heteroduplexes.These experiments show that the correction of thenumber of copies found by competitive PCR byconsidering the percentage of heteroduplexes allows amore accurate quantification of the number of targetcopies present in mt DNA samples.The design of internal standards specific to thefragment resulting from other deletions could alsohelp a more accurate quantification of thefrequency of other mt DNA deletions as well,and reconsideration of the role of mt DNA deletions inageing.