The evolutionary transformation of phyllopodous to stenopodous limbs in the Branchiopoda (Crustacea)--is there a common mechanism for early limb development in arthropods?
The evolutionary transformation of phyllopodous to stenopodous limbs in the Branchiopoda (Crustacea)--is there a common mechanism for early limb development in arthropods?
复制标题
鳃足纲（甲壳纲）叶足向窄足的进化转变——节肢动物早期肢体发育是否存在共同机制？
DOI：
10.1387/ijdb.11804030
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
G. Scholtz
中科院分区：
文献类型：
--
作者：
J. Olesen;S. Richter;G. Scholtz
节肢动物，特别是甲壳类动物的肢体形态表现出很大的多样性。这使得肢体及其部分的同源化以及我们对这些肢体类型的进化转化的理解成为问题。为了解决这些问题，我们进行了比较研究的肢体发育的两个代表的鳃足类甲壳动物，一个叶足的其他stenopodous躯干四肢。用扫描电镜、Hoechst荧光染色和Distal-less基因表达等方法研究了大鳃足类Cyclestheria hislopi（Conchostraca）和捕食类枝角类Leptodora kindtii（Haplopoda）的躯干肢个体发育。C.躯干肢的早期个体发育。hislopi和L. kindtii是类似的。在这两个物种的肢体形成腹放置，延长，细分的肢芽。然而，在C. hislopi的早期肢芽部分最终构成叶足滤肢的内突和内足，而L. kindtii，类似的肢芽部分最终构成了成年人分节，狭足和捕食躯干肢的实际部分。因此，C. hislopi（和其他“较大的鳃足类”）与L. kindtii。这是最简约的假设，分段的躯干四肢在L。kindtii是从有端部的叶足肢发育而来的，而不是相反。这项研究已经证明了至少一种方式，其中分节肢已来自叶足，多裂肢在进化过程中。在其他甲壳类动物的狭足、分节和单肢肢的进化过程中，也可以假设有类似的途径。尽管成年节肢动物的肢体形态存在差异，但其早期的模式化似乎遵循类似的原则。
Arthropods and in particular crustaceans show a great diversity concerning their limb morphology. This makes the homologization of limbs and their parts and our understanding of evolutionary transformations of these limb types problematical. To address these problems we undertook a comparative study of the limb development of two representatives of branchiopod crustaceans, one with phyllopodous the other with stenopodous trunk limbs. The trunk limb ontogeny of a 'larger branchiopod', Cyclestheria hislopi ('Conchostraca') and the raptorial cladoceran Leptodora kindtii (Haplopoda) has been examined by various methods such as SEM, Hoechst fluorescent stain and expression of the Distal-less gene. The early ontogeny of the trunk limbs in C. hislopi and L. kindtii is similar. In both species the limbs are formed as ventrally placed, elongate, subdivided limb buds. However, in C. hislopi, the portions of the early limb bud end up constituting the endites and the endopod of the phyllopodous filtratory limb in the adult, whereas in L. kindtii, similar limb bud portions end up constituting the actual segments in the segmented, stenopodous, and raptorial trunk limbs of the adults. Hence, the portions of the limbs corresponding to the endites of the phyllopodous trunk limbs in C. hislopi (and other 'larger branchiopods') are homologous to the segments of the stenopodous trunk limbs in L. kindtii. It is most parsimonious to assume that the segmented trunk limbs in L. kindtii have developed from phyllopodous limbs with endites and not vice versa. This study has demonstrated at least one way in which segmented limbs have been derived from phyllopodous, multi-lobate limbs during evolution. Similar pathways can be assumed for the evolution of stenopodous, segmented and uniramous limbs in other crustaceans. Irrespective of the differences in the adult limb morphology, the early patterning of arthropod limbs seems to follow a similar principle.