Miyazaki S, Shimoji H, Suzuki R, Chinushi I, Takayanagi H, Yaguchi H, Miura T, Maekawa K
Graduate School of Agriculture, Tamagawa University, Tokyo, Japan.
Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Insect Mol Biol. 2021 Feb;30(1):113-121. doi: 10.1111/imb.12682. Epub 2020 Nov 12.
In eusocial insect colonies, non-reproductive workers often perform different tasks. Tasks of an individual worker are shifted depending on various factors, e.g., age and colony demography. Although a vitellogenin (Vg) gene play regulatory roles in both reproductive and non-reproductive division of labours in a honeybee, it has been shown that the insect Vg underwent multiple gene duplications and sub-functionalisation, especially in apical ant lineages. The regulatory roles of duplicated Vgs were suggested to change evolutionarily among ants, whereas such roles in phylogenetically basal ants remain unclear. Here, we examined the expression patterns of conventional Vg (CVg), Vg-like A, Vg-like B and Vg-like C, as well as Vg receptor, during the task shift in an age-dependent manner and under experimental manipulation of colony demography in a primitive ant Diacamma sp. Expressions of CVg and Vg-like A in a brain were associated with a nursing task. It is suggested that associations of brain expressions of these Vgs with worker tasks were acquired in the basal ant lineage, and that such Vg functions could have sub-functionalised in the derived ant lineage.
在群居性昆虫群落中，不具备繁殖能力的工蚁通常会执行不同的任务。单个工蚁的任务会根据各种因素而发生变化，例如年龄和群落人口统计学特征。虽然卵黄原蛋白（Vg）基因在蜜蜂的繁殖性和非繁殖性劳动分工中都发挥着调节作用，但研究表明，昆虫的Vg经历了多次基因复制和亚功能化，尤其是在高等蚂蚁谱系中。有研究认为，复制后的Vg的调节作用在蚂蚁中会发生进化变化，而在系统发育上处于基部的蚂蚁中，这些作用仍不清楚。在这里，我们以年龄依赖的方式，并在对原始蚂蚁Diacamma sp.群落人口统计学进行实验操作的情况下，研究了传统Vg（CVg）、Vg-like A、Vg-like B和Vg-like C以及Vg受体在任务转变过程中的表达模式。大脑中CVg和Vg-like A的表达与护理任务相关。研究表明，这些Vg在大脑中的表达与工蚁任务之间的关联是在基部蚂蚁谱系中获得的，并且这种Vg功能可能在衍生蚂蚁谱系中发生了亚功能化。
