线粒体基因组的遗传特点呈母系传递。线粒体有自己独立的基因组,并且线粒体DNA(mt DNA)具有与核基因组不同的结构和代码,mt DNA基因组编码可产生部分线粒体呼吸链的多肽蛋白。如果mt DNA发生突变,依照其表型受累的程度,可将其归类为:1严重程度,为罕见、高遗传(保守)性的因果性突变,常引起一系列神经系统、肌肉、心脏和内分泌器官严重的人类单基因疾病;2中等程度或轻度突变,常引起常见的复杂性疾病和迟发性及老年相关疾病,如帕金森氏病和阿尔兹海默病。另外,多数健康人也会带有低水平(〈1%)的mt DNA点突变,包括先天遗传性突变和后天获得性突变。其中随着获得性突变数量的增加,当超过特定阈值水平时,会导致老年相关疾病的发生。本文内也依据现有模式生物的研究结果,提供有人们对mt DNA突变机制的新知识。
The genetic characteristics of mitochondrial genome are maternal transmission. Mitochondria have their own independent genome,and mitochondrial DNA( mt DNA) has a different structure and codes from the nuclear genome. The mt DNA encodes a polypeptide protein that produces a part of components in mitochondrial respiratory chain. If mt DNA is mutated,it is classified as: 1severity,a rare,high genetic( conserved) causal mutation,which causes a series of neurological,muscular,cardiac,and endocrine disorders,depending on the extent of phenotypic involved organism serious human monogenic disease; 2moderate or mild mutation,often caused by the common complex diseases and late and old age-related diseases. In addition,most healthy individuals also carry low levels( 〈1%) of mt DNA point mutations,including congenital and acquired mutations. With the increase in the number of acquired mutations,when a certain threshold level is exceeded,a late onset of disease may occur. In this paper,we also provide some new knowledge about mt DNA mutation mechanism based on the results of existing model organisms.