Institute of Legal Medicine, University of Münster, Röntgenstrasse 23, Münster, Germany.
Int J Legal Med. 2010 Mar;124(2):133-42. doi: 10.1007/s00414-009-0385-0.
We present allelic data for three known and one new C-tract in the human mitochondrial DNA (mtDNA) control region, and we measure intergenerational mutation rates at such C-tracts. In detail, in a sample of 1,172 mtDNA sequences, we demonstrate the existence of an instability threshold of eight consecutive cytosines, at and above which the phenomenon of length heteroplasmy arises. To determine mutation rates, we draw on mtDNA sequences in up to four generations of 248 pedigrees for families living in high or low-radiation environmental conditions. The high-radiation sample gives the most conservative (fastest) mutation rate likely to be encountered in any forensic context. We find that the C-tract mutation rate is up to 6% per generation, and we observe an excess of cytosine gains over losses. Case studies and guidelines for evaluating mtDNA heteroplasmy are provided.
我们呈现了人类线粒体 DNA（mtDNA）控制区中三个已知和一个新的 C 链段的等位基因数据，并测量了这些 C 链段的代际突变率。具体来说，在 1172 个 mtDNA 序列的样本中，我们证明了存在一个连续八个胞嘧啶的不稳定性阈值，超过这个阈值，长度异质性现象就会出现。为了确定突变率，我们利用生活在高或低辐射环境条件下的 248 个家系的多达四代 mtDNA 序列。高辐射样本给出了最保守（最快）的突变率，这可能在任何法医学背景下都会遇到。我们发现 C 链段的突变率高达每代 6%，并且我们观察到胞嘧啶的获得超过了缺失。我们提供了案例研究和评估 mtDNA 异质性的指导方针。
