Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Gronostajowa 9, 30-387 Krakow, Poland.
Genes (Basel). 2020 Jan 16;11(1):104. doi: 10.3390/genes11010104.
The most important role of mitochondria is to supply cells with metabolic energy in the form of adenosine triphosphate (ATP). As synthesis of ATP molecules is accompanied by the generation of reactive oxygen species (ROS), mitochondrial DNA (mtDNA) is highly vulnerable to impairment and, consequently, accumulation of deleterious mutations. In most animals, mitochondria are transmitted to the next generation maternally, i.e., exclusively from female germline cells (oocytes and eggs). It has been suggested, in this context, that a specialized mechanism must operate in the developing oocytes enabling escape from the impairment and subsequent transmission of accurate (devoid of mutations) mtDNA from one generation to the next. Literature survey suggest that two distinct and irreplaceable pathways of mitochondria transmission may be operational in various animal lineages. In some taxa, the mitochondria are apparently selected: functional mitochondria with high inner membrane potential are transferred to the cells of the embryo, whereas those with low membrane potential (overloaded with mutations in mtDNA) are eliminated by mitophagy. In other species, the respiratory activity of germline mitochondria is suppressed and ROS production alleviated leading to the same final effect, i.e., transmission of undamaged mitochondria to offspring, via an entirely different route.
线粒体最重要的作用是以三磷酸腺苷（ATP）的形式为细胞提供代谢能量。由于 ATP 分子的合成伴随着活性氧（ROS）的产生，线粒体 DNA（mtDNA）极易受损，因此会积累有害突变。在大多数动物中，线粒体通过母系遗传传递给下一代，即仅从雌性生殖细胞（卵母细胞和卵子）中传递。在这种情况下，有人提出，一种特殊的机制必须在发育中的卵母细胞中发挥作用，以使卵母细胞能够逃避损伤，并将准确的（无突变）mtDNA 从一代传递到下一代。文献综述表明，在不同的动物谱系中，可能存在两种不同的、不可替代的线粒体传递途径。在某些分类群中，线粒体显然是被选择的：具有高内膜电位的功能线粒体被转移到胚胎细胞中，而那些膜电位较低（mtDNA 突变过多）的线粒体则通过线粒体自噬被消除。在其他物种中，生殖线粒体的呼吸活性受到抑制，ROS 产生减轻，导致通过完全不同的途径将未受损的线粒体传递给后代，最终达到相同的效果。
