Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0123, Japan.
J Plant Res. 2010 Mar;123(2):163-70. doi: 10.1007/s10265-009-0295-8.
To analyze mitochondrial DNA (mtDNA)inheritance, differences in mtDNA between Chlamydomonas reinhardtii and Chlamydomonas smithii, respiration deficiency and antibiotic resistance were used to distinguish mtDNA origins. The analyses indicated paternal inheritance. However, these experiments raised questions regarding whether paternal inheritance occurred normally.Mitochondrial nucleoids were observed in living zygotes from mating until 3 days after mating and then until progeny formation. However, selective disappearance of nucleoids was not observed. Subsequently, experimental serial backcrosses between the two strains demonstrated strict paternal inheritance. The fate of mt+ and mt- mtDNA was followed using the differences in mtDNA between the two strains. The slow elimination of mt+ mtDNA through zygote maturation in darkness was observed, and later the disappearance of mt+ mtDNA was observed at the beginning of meiosis. To explain the different fates of mtDNA, methylation status was investigated; however, no methylation was detected. Variously constructed diploid cells showed biparental inheritance. Thus, when the mating process occurs normally, paternal inheritance occurs. Mutations disrupting mtDNA inheritance have not yet been isolated. Mutations that disrupt maternal inheritance of chloroplast DNA (cpDNA) do not disrupt inheritance of mtDNA. The genes responsible for mtDNA inheritance are different from those of chloroplasts.
为了分析线粒体 DNA（mtDNA）的遗传方式，我们比较了莱茵衣藻（Chlamydomonas reinhardtii）和史密斯衣藻（Chlamydomonas smithii）之间 mtDNA 的差异、呼吸缺陷和抗生素抗性，以此来区分线粒体 DNA 的起源。分析表明其遗传方式为父系遗传。然而，这些实验引发了一些问题，即父系遗传是否正常发生。在交配后的活体合子中观察到线粒体核体，直到交配后 3 天，然后直到后代形成。然而，没有观察到核体的选择性消失。随后，对这两个菌株进行的实验系列回交表明，其遗传方式严格为父系遗传。通过两种菌株之间 mtDNA 的差异，追踪 mt+和 mt- mtDNA 的命运。在黑暗中通过合子成熟缓慢消除 mt+ mtDNA，随后在减数分裂开始时观察到 mt+ mtDNA 的消失。为了解释 mtDNA 的不同命运，我们研究了甲基化状态，但未检测到甲基化。构建的各种二倍体细胞显示出双亲遗传。因此，当交配过程正常发生时，会发生父系遗传。尚未分离出破坏 mtDNA 遗传的突变。破坏叶绿体 DNA（cpDNA）母系遗传的突变不会破坏 mtDNA 的遗传。负责 mtDNA 遗传的基因与负责叶绿体的基因不同。
