Comparative mutagenesis of human cells in vitro and in vivo. Final progress report, 1 November 1995--31 October 1996

Abstract

By combining the separation technology of CDCE (constant denaturing capillary electrophoresis) with high fidelity DNA amplification the authors devised a reliable means to measure mutant fractions of any and all point mutations in human cell or tissue mitochondrial DNA arising at mutant fractions at or above 10 {sup {minus}6}. Measurements in nuclear genes are more difficult than in mitochondrial genes. First, the average mutant fractions per base pair in middle-aged human T cells` hprt gene are about 10{sup {minus}8} which is much lower than the approximately 3 {times} 10{sup {minus}6} they have found for mitochondrial point mutations in several human tissues. To see point mutational nuclear hotspots they need an analytical procedure which is reliable at mutant fractions of 10{sup {minus}7} and higher. Fortunately, they are close to that goal. At this writing, reconstruction experiments with human cells indicate they have achieved a sensitivity at least as low as 5 {times} 10{sup {minus}7} so they are optimistic that they can reach the required criterion.