Shibata Takehiko, Ling Feng
Cellular & Molecular Biology Laboratory, RIKEN (The Institute of Physical and Chemical Research), Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan.
Mitochondrion. 2007 Feb-Apr;7(1-2):17-23. doi: 10.1016/j.mito.2006.11.024. Epub 2006 Dec 12.
Homoplasmy is a basic genetic state of mitochondria, in which all of the hundreds to thousands of mitochondrial (mt)DNA copies within a cell or an individual have the same nucleotide-sequence. It was recently found that "vegetative segregation" to generate homoplasmic cells is an active process under genetic control. In the yeast Saccharomyces cerevisiae, the Mhr1 protein which catalyzes a key reaction in mtDNA homologous recombination, plays a pivotal role in vegetative segregation. Conversely, within the nuclear genome, homologous DNA recombination causes genetic diversity. Considering these contradictory roles of this key reaction in DNA recombination, possible functions of homoplasmy are discussed.
同质性是线粒体的一种基本遗传状态，在这种状态下，细胞或个体内成百上千个线粒体（mt）DNA拷贝都具有相同的核苷酸序列。最近发现，产生同质性细胞的“营养分离”是一个受遗传控制的活跃过程。在酿酒酵母中，催化mtDNA同源重组关键反应的Mhr1蛋白在营养分离中起关键作用。相反，在核基因组中，同源DNA重组会导致遗传多样性。考虑到DNA重组中这一关键反应的这些相互矛盾的作用，本文讨论了同质性可能具有的功能。
