Zhao Fang, Morandin Claire, Jiang Kai, Su Tianjuan, He Bo, Lin Gonghua, Huang Zuhao
School of Life Sciences Jinggangshan University Ji'an China.
Department of Ecology and Evolution, Biophore University of Lausanne Lausanne Switzerland.
Ecol Evol. 2021 Jun 5;11(13):8983-8992. doi: 10.1002/ece3.7736. eCollection 2021 Jul.
Vitellogenin (Vg), a storage protein, has been significantly studied for its egg yolk precursor role in oviparous animals. Recent studies found that vitellogenin and its Vg-like homologs were fundamentally involved in many other biological processes in social insects such as female caste differences and oxidative stress resilience. In this study, we conducted the first large-scale molecular evolutionary analyses of vitellogenin coding genes () and genes of bumble bees, a primitively eusocial insect belonging to the genus Bombus. We obtained sequences for each of the four genes (, , , and ) from 27 bumble bee genomes (nine were newly sequenced in this study), and sequences from the two closest clades of , including five species and five . Our molecular evolutionary analyses show that in bumble bee, the conventional experienced strong positive selection, while the genes showed overall relaxation of purifying selection. In and however, all four genes were found under purifying selection. Furthermore, the conventional showed signs of strong positive selection in most subgenera in , apart from the obligate parasitic subgenus which has no caste differentiation. Together, these results indicate that the conventional , a key pleiotropic gene in social insects, is the most rapidly evolving copy, potentially due to its multiple known social functions for both worker and queen castes. This study shows that concerted evolution and purifying selection shaped the evolution of the gene family following their ancient gene duplication and may be the leading forces behind the evolution of new potential protein function enabling functional social pleiotropy.
卵黄原蛋白（Vg）是一种储存蛋白，因其在卵生动物中作为蛋黄前体的作用而受到广泛研究。最近的研究发现，卵黄原蛋白及其Vg样同源物在社会性昆虫的许多其他生物学过程中起着重要作用，如雌性蜂型差异和氧化应激恢复能力。在本研究中，我们对卵黄原蛋白编码基因（）和熊蜂（Bombus属的一种原始社会性昆虫）的基因进行了首次大规模分子进化分析。我们从27个熊蜂基因组（本研究中新测序了9个）中获得了四个基因（，，，和）的序列，以及来自两个最接近进化枝的序列，包括五个物种和五个。我们的分子进化分析表明，在熊蜂中，传统的经历了强烈的正选择，而基因总体上显示出纯化选择的放松。然而，在和中，所有四个基因都处于纯化选择之下。此外，除了没有蜂型分化的专性寄生亚属外，传统的在大多数亚属中都显示出强烈正选择的迹象。总之，这些结果表明，传统的是社会性昆虫中的一个关键多效性基因，可能由于其对工蜂和蜂王蜂型的多种已知社会功能，是进化最快的拷贝。这项研究表明，协同进化和纯化选择在基因家族古老的基因复制后塑造了其进化，可能是新的潜在蛋白质功能进化背后的主导力量，从而实现功能性社会多效性。
