Arai Hiroshi, Watada Masayoshi, Kageyama Daisuke
National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki 305-0851, Japan.
Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 780-8857, Japan.
R Soc Open Sci. 2024 Jan 10;11(1):231502. doi: 10.1098/rsos.231502. eCollection 2024 Jan.
Insects harbour diverse maternally inherited bacteria and viruses, some of which have evolved to kill the male progeny of their hosts (male killing: MK). The fly species carries a maternally transmitted MK-inducing partiti-like virus, but it was unknown if it carries other MK-inducing endosymbionts. Here, we identified two male-killing strains (Biau1 and Biau2) from and compared their genomes to elucidate their evolutionary processes. The two strains were genetically closely related but had exceptionally different genome structures with considerable rearrangements compared with combinations of other strains. Despite substantial changes in the genome structure, the two strains did not experience gene losses that would disrupt the male-killing expression or persistence in the host population. The two -infected matrilines carried distinct mitochondrial haplotypes, suggesting that Biau1 and Biau2 have invaded independently and undergone considerable genome changes owing to unknown selective pressures in evolutionary history. This study demonstrated the presence of three male-killers from two distinct origins in one fly species and highlighted the diverse and rapid genome evolution of MK in the host.
昆虫携带着多种母系遗传的细菌和病毒，其中一些已经进化到能够杀死宿主的雄性后代（雄性致死：MK）。这种蝇类携带一种母系传播的诱导MK的类Partiti病毒，但尚不清楚它是否携带其他诱导MK的内共生体。在这里，我们从该蝇类中鉴定出两个雄性致死菌株（Biau1和Biau2），并比较它们的基因组以阐明其进化过程。这两个菌株在遗传上密切相关，但与其他该蝇类菌株的组合相比，它们具有异常不同的基因组结构，存在大量重排。尽管基因组结构发生了重大变化，但这两个该蝇类菌株并未经历会破坏雄性致死在宿主种群中的表达或持续性的基因丢失。这两个感染该蝇类的母系携带不同的线粒体单倍型，表明Biau1和Biau2是独立侵入该蝇类的，并且由于进化历史中未知的选择压力而经历了相当大的基因组变化。这项研究证明了在一种蝇类中存在来自两个不同起源的三种雄性致死因子，并突出了宿主中MK内共生体多样且快速的基因组进化。
