Compound eye evolution: Highly conserved retinula and cone cell patterns indicate a common origin of the insect and crustacean ommatidium
Compound eye evolution: Highly conserved retinula and cone cell patterns indicate a common origin of the insect and crustacean ommatidium
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DOI：
10.1007/s001140050442
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发表时间：
1997-12-01
影响因子：
--
通讯作者：
Smola, U
中科院分区：
文献类型：
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作者：
Melzer, RR;Diersch, R;Smola, U
甲壳动物和昆虫的复眼具有许多相应的结构元件。然而，缺乏它们同源性的确凿证据，也不清楚它们的前身是如何组织的。最近对复眼发育的研究表明，构成小眼的单个细胞的排列是由高度特异性的图案化过程引起的。这表明检查小眼细胞模式进行比较分析的重要性。为了更好地了解甲壳类复眼的基本细胞排列，我们因此研究了两个祖先的背介类，Triops和Lasserurus（Phyllopoda）的小网膜和视锥细胞。在这些物种与其他甲壳类动物和昆虫之间进行的比较表明，这些细胞的模式在两组之间是高度保守的。与昆虫一样，在小眼的8个小网膜或R细胞中，6个排列成3对，表现出两侧对称性（R1/R6，R2/R5，R3/R4，如果使用Dietrich（1909）的命名法进行标记），而在小眼的主轴上发现了两个单细胞（R7和R8）。R细胞R1/R2、R3/R4、R5/R6和R8/R1之间的突起起源于两对视锥细胞或C细胞。这种模式可能代表了上颚视觉系统的祖先状态，并支持了它们的复眼具有单系起源的观点。甲壳纲和昆虫纲的主要视觉器官是由规则排列的亚单位小眼组成的复眼。尽管这些亚基的高度特异性的结构元件，如表皮小面，晶锥和R细胞形成的横纹，发生在几乎每一个复眼研究，有很多关于它们的进化起源的争议，从这两个群体的复眼进化几次收敛，单系起源的想法（见[1]的审查）。Paulus [2]强调了不同细胞类型的相同数量，即8个R细胞，4个C细胞和2个角质细胞或初级色素细胞作为后一种理论的支持。此外，在比较研究中使用了各种特征，例如复眼支配的视神经末梢中高度对应的同构神经元组[3]，组胺作为节肢动物R细胞神经递质的出现[4]，视锥细胞特异性糖蛋白的存在[5]，以及眼睛发育的共同主控基因[6]。在过去的十年里，对果蝇复眼发育的研究表明，细胞在果蝇复眼中的发育是由细胞的发育决定的。
The compound eyes of crustaceans and insects are characterized by numerous corresponding structural elements. Conclusive evidence for their homology, however, is lacking and it is not clear how their predecessor may have been organized. Recent studies on compound eye development have shown that the arrangement of the individual cells contributing to an ommatidium is brought about by highly specific patterning processes. This indicates the importance of examining ommatidial cell patterns for comparative analysis. In order to better understand the basic cell arrangement of the crustacean compound eye, we have therefore studied the retinula and cone cells in two ancestral notostracans, Triops and Lepidurus (Phyllopoda). A comparison made between these species and other crustaceans, and insects, indicates that the pattern of these cells is strongly conserved between the two groups. As in insects, among the eight retinula or R-cells of an ommatidium, six are arranged in three pairs exhibiting bilateral symmetry (R1/R6, R2/R5, R3/R4, if one uses Dietrich’s (1909) nomenclature for labelling), while two single cells are found in the ommatidia’s main axis (R7 and R8). Processes projecting between R-cells R1/R2, R3/R4, R5/R6 and R8/R1 originate from two pairs of cone or C-cells. This pattern might represent an ancestral condition of the mandibulate visual system and lends support to the idea that their compound eyes have a monophyletic origin.The main visual organs of Crustacea and Insecta are compound eyes made of regularly arrayed subunits called ommatidia. Despite the highly specific structural elements of these subunits such as cuticular facets, crystalline cones and R-cells forming the rhabdom that occur in almost every compound eye studied, there has been much controversy about their evolutionary origin, ranging from the idea that the compound eyes of these two groups evolved several times convergently, to that of a monophyletic origin (see [1] for review). Paulus [2] stressed the identical numbers of the different cell types, ie eight R-cells, four C-cells and two corneagenous or primary pigment cells as support for the latter theory. In addition, a variety of features has been used in comparative studies, eg the highly corresponding set of isomorphic neurons in the optic neuropils innervated by compound eyes [3], the occurrence of histamine as neurotransmitter of arthropod R-cells [4], the presence of a cone-specific glycoprotein [5], and of a common master control gene for eye development [6]. In the past decade, studies on the development of the Drosophila compound eye have shown that the cellu-