Bopp Daniel
Institute of Molecular Life Sciences, University of Zurich, Wintherthurerstrasse, Zurich, Switzerland.
J Genet. 2010 Sep;89(3):315-23. doi: 10.1007/s12041-010-0043-9.
Through the decades of relentless and dedicated studies in Drosophila melanogaster, the pathway that governs sexual development has been elucidated in great detail and has become a paradigm in understanding fundamental cell-fate decisions. However, recent phylogenetic studies show that the molecular strategy used in Drosophila deviates in some important aspects from those found in other dipteran flies and suggest that the Drosophila pathway is likely to be a derivative of a simpler and more common principle. In this essay, I will discuss the evolutionary plasticity of the sex-determining pathway based on studies in the common housefly, Musca domestica. Diversification appears to primarily arise from subtle differences in the regulation of the key switch gene transformer at the top of the pathway. On the basis of these findings I propose a new idea on how the Drosophila pathway may have evolved from a more archetypal system such as in M. domestica. In essence, the arrival of an X counting mechanism mediated by Sex-lethal to compensate for X linked gene dose differences set the stage for an intimate coupling of the two pathways. Its precedent recruitment to the dosage compensation pathway allowed for an intervention in the regulation of transformer where it gradually and eventually' completely substituted for a need of transformer autoregulation.
经过数十年来对黑腹果蝇坚持不懈且专注的研究，调控性别发育的通路已被详细阐明，并成为理解基本细胞命运决定的范例。然而，最近的系统发育研究表明，果蝇中使用的分子策略在一些重要方面与其他双翅目昆虫不同，这表明果蝇的通路可能是一个更简单、更普遍原则的衍生物。在本文中，我将基于对家蝇（Musca domestica）的研究，探讨性别决定通路的进化可塑性。多样化似乎主要源于通路顶端关键开关基因transformer调控的细微差异。基于这些发现，我提出了一个关于果蝇通路可能如何从如家蝇这样更原始的系统进化而来的新观点。本质上，由性致死基因（Sex-lethal）介导的X染色体计数机制的出现，以补偿X连锁基因剂量差异，为这两条通路的紧密耦合奠定了基础。它先前被招募到剂量补偿通路中，使得能够对transformer的调控进行干预，在此过程中它逐渐并最终完全取代了transformer自我调节的需求。
