The eyes have it: genetic, morphological and functional analysis of differences in compound eyes between Drosophila species

眼睛有它：果蝇物种间复眼差异的遗传、形态和功能分析

• 批准号: BB/T000317/2
• 负责人: Alistair McGregor
• 金额: $ 34.73万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FT000317%2F2
• 关键词: eyes; genetic; morphological; functional; analysis

Vision is one of the major sensory systems that helps animals navigate through the environment. There is great variation among the eyes of animals reflecting evolutionary adaptations in behaviour and habitat. Two major parameters that determine the quality of vision are: 1) How easily can objects be discriminated at different levels of light luminescence (contrast sensitivity) and 2) how far apart do two objects have to be to be detected discriminated (acuity). Contrast sensitivity depends on the amount of light absorbed by the eye's photoreceptors and therefore on the size of the eye and photoreceptor sensitivity. Acuity on the other hand depends on the density of those light-sensitive photoreceptors, for example, the density of rods and cones in the retina of the human eye. The same rules generally apply to the compound eyes of insects, which are made up of smaller eyes, called ommatidia. Larger ommatidia with larger lens diameters to collect photons gives higher contrast sensitivity. However, acuity depends on the density of ommatidia - more ommatidia per eye area gives higher acuity, and therefore there can be a trade off between contrast sensitivity and acuity determined by the size and number of ommatidia. The size of ommatidia and overall eye size varies greatly among insects, but we still know very little about the genes underlying these evolutionary differences, how this changes the development of eyes, and how these changes in eye morphology alter the vision of these animals. We have found that the gene orthodenticle (otd) causes differences in ommatidia diameter and overall eye size between the closely related species Drosophila mauritiana and Drosophila simulans. We now propose to use a range of approaches to understand how otd regulates ommatidia size and how this gene makes larger eyes in D. mauritiana, and the consequences for their vision. We will first further study the role of otd in specification of ommatidia size in the model organism D. melanogaster to learn more about the mechanisms involved. We will then put the D. mauritiana version of otd into a D. simulans genetic background and vice versa, resulting in a D. simulans fly with a D. mauritiana-like eye and the other way around. These flies can then be compared to pure D. simulans and D. mauritiana flies in their regulation of eye development, eye morphology, neuronal activity and their actual vision. The results of these experiments will reveal how natural genetic variation alters eye development to produce eyes with different optics and how this affects the vision of these flies. This will help us to better understand insect vision generally and provide new insights into how the great diversity of insect eyes and the vision of these animals have evolved. In addition, since there are major similarities between invertebrate and vertebrate eye development, including important roles of otd and its homologues, this project could provide new information about eye development more broadly in animals including humans.

视觉是帮助动物在环境中导航的主要感觉系统之一。动物的眼睛有很大的差异，反映了行为和栖息地的进化适应。决定视觉质量的两个主要参数是：1）在不同的发光水平下物体被区分的难易程度（对比敏感度）和2）两个物体必须被检测区分的距离（敏锐度）。对比敏感度取决于眼睛感光器吸收的光量，因此也取决于眼睛的大小和感光器的敏感度。另一方面，敏锐度取决于那些光敏光感受器的密度，例如，人眼视网膜中的视杆细胞和视锥细胞的密度。同样的规则也适用于昆虫的复眼，复眼由较小的眼睛组成，称为小眼。具有较大透镜直径的较大小眼用于收集光子，从而提供较高的对比灵敏度。然而，敏锐度取决于小眼的密度-每个眼睛区域的小眼越多，敏锐度越高，因此可以在对比敏感度和由小眼的大小和数量决定的敏锐度之间进行权衡。小眼的大小和整个眼睛的大小在昆虫中差异很大，但我们仍然对这些进化差异背后的基因知之甚少，这如何改变眼睛的发育，以及这些眼睛形态的变化如何改变这些动物的视力。我们已经发现，基因orthodenticle（otd）的小眼直径和整体眼睛的大小密切相关的物种毛里求斯果蝇和果蝇simulans之间的差异。我们现在建议使用一系列的方法来了解otd如何调节小眼的大小，以及该基因如何使D.毛里求斯，以及对他们愿景的影响。我们将首先进一步研究otd在模式生物D中小眼大小规格中的作用。了解更多有关的机制。我们将把D。mauritiana版本的otd转化为D. simulans遗传背景，反之亦然，导致D. simulans飞行时带D.毛里求斯式的眼睛和周围的其他方式。这些果蝇可以与纯D. simulans和D. mauritiana果蝇在眼睛发育、眼睛形态、神经元活动和实际视力的调节方面的作用。这些实验的结果将揭示自然遗传变异如何改变眼睛发育，以产生具有不同光学特性的眼睛，以及这如何影响这些果蝇的视力。这将帮助我们更好地了解昆虫的视觉，并为昆虫眼睛的巨大多样性和这些动物的视觉是如何进化的提供新的见解。此外，由于无脊椎动物和脊椎动物的眼睛发育有很大的相似性，包括otd及其同源物的重要作用，该项目可以提供更广泛的动物包括人类眼睛发育的新信息。

项目成果

Evolution of compound eye morphology underlies differences in vision between closely related Drosophila species

复眼形态的进化是密切相关的果蝇物种之间视力差异的基础

• DOI: 10.1101/2023.07.16.549164
• 发表时间: 2023
• 作者: Buffry A