Maternally transmitted non-bacterial male killer in Drosophila biauraria

A maternally inherited, all-female trait is widely found among arthropods, which is caused by bacterial endosymbionts such as Wolbachia, Rickettsia, Spiroplasma and Cardinium We discovered a single female of Drosophila biauraria, collected from Tomakomai, Hokkaido, Japan, that produced all-female offspring. This all-female trait was maternally inherited in the iso-female line (SP12F) by backcrossing with males of a normal line (SP11-20) with a 1:1 sex ratio derived from the same population. The all-female trait was not affected by tetracycline treatment performed for two consecutive generations. However, the microinjection of filter-sterilised homogenate of SP12F females into SP11-20 females established all-female matrilines. Our data suggest the role of transmissible agents, most likely viruses, but not bacteria or protists, as the possible cause of the all-female phenotype, which is likely to be achieved by killing of male embryos because egg hatch rates of SP12F were nearly half as t...

母系遗传的全雌性性状广泛分布于节肢动物中，此类性状多由沃尔巴克氏体（Wolbachia）、立克次体（Rickettsia）、螺原体（Spiroplasma）与卡氏菌（Cardinium）等细菌内共生体引发。我们在日本北海道苫小牧市采集的双斑果蝇（Drosophila biauraria）种群中，发现了一只仅能产生全部雌性后代的雌性个体。该全雌性性状在同雌品系SP12F中表现为母系遗传：我们将该品系雌虫与来自同一种群、性比为1:1的正常品系SP11-20的雄虫进行回交，验证了这一遗传模式。连续两代使用四环素处理后，该全雌性性状并未受到影响。然而，将SP12F雌虫的过滤除菌匀浆显微注射至SP11-20雌虫体内后，成功建立了全雌性母系谱系。我们的研究数据表明，可传播因子（极有可能为病毒，而非细菌或原生生物）是该全雌性表型的潜在诱因；该性状大概率通过杀死雄性胚胎实现，因为SP12F的卵孵化率仅约为正常水平的一半……