Robertson A J, Bech-Hansen N T, Rank G H
Can J Genet Cytol. 1975 Sep;17(3):381-9. doi: 10.1139/g75-050.
An unusual property of GR25a [rho+] was the production of 20 to 30 percent [rho-] zygote colonies when crossed to a tester strain lacking mitochondrial DNA. Spontaneous [rho-] isolates of GR25a [rho+] were observed to be highly suppressive and to contain mitochondrial DNA of a parental buoyant density (1.685 g/cm3). Three ethidium bromide induced neutral petites of GR25 a [rho+] did not have detectable mitochondrial DNA and were neutral in crosses to [rho+] strains. Seven [rho-] zygote colony isolates obtained from crossing GR25a [rho+] to a neutral peptite were shown to contain abnormal mitochondrial DNA. Six zygote colony isolates had mitochondrial DNA of a buoyant density less than, or equal to, GR25a (1.682 - 1.685 g/cm3), whereas one isolate had a buoyant density greater than GR25a (1.688 g/cm3). It was suggested that abnormal mitochondrial DNA is generated during the mating reaction.
GR25a [rho+] 的一个不同寻常的特性是，当与缺乏线粒体DNA的测试菌株杂交时，会产生20%至30%的[rho-]合子菌落。观察到GR25a [rho+] 的自发[rho-]分离株具有高度抑制性，并且含有亲本浮力密度（1.685 g/cm³）的线粒体DNA。三个溴化乙锭诱导的GR25 a [rho+] 的中性小菌落没有可检测到的线粒体DNA，并且在与[rho+]菌株杂交时呈中性。从GR25a [rho+] 与中性小菌落杂交获得的七个[rho-]合子菌落分离株显示含有异常线粒体DNA。六个合子菌落分离株的线粒体DNA浮力密度小于或等于GR25a（1.682 - 1.685 g/cm³），而一个分离株的浮力密度大于GR25a（1.688 g/cm³）。有人提出，异常线粒体DNA是在交配反应过程中产生 的。
