Morphometric and Genetic Description of Trophic Adaptations in Cichlid Fishes.
Morphometric and Genetic Description of Trophic Adaptations in Cichlid Fishes.
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慈鲷类鱼类营养适应的形态计量学和遗传学描述。
作者：
头骨和下巴的形状对动物的进食方式至关重要。这项工作的目的是研究面部变化如何演变以及这些变化的遗传基础。我们使用了两种不同面部形状的马拉维湖慈鲷，一种已经进化到通过吸食来捕食猎物，另一种是从岩石上咬藻类，以及两种物种人工交配产生的杂交个体。我们发现颅面结构发生了一系列变化，包括下颌和喉咙区域的形状，这些变化会影响动物在吸食和咬合时的表现。然后，我们确定了调节这些面部形状的遗传区域。这些遗传区域表明，感官的进化以及其他特征可能在面部进化中发挥重要作用。此外，面部不同部位的进化受不同的遗传区域控制。尽管如此，以相似方式进食的慈鲷科鱼类具有相似的面部形状，这表明下颌运动的功能对慈鲷科鱼类的面部进化有一定的限制。总的来说，这项工作提供了关于面部如何进化的见解，这些变化如何与进食有关，以及调节颅面变化的基因和分子。自达尔文以来，生物学家一直试图了解表型适应的进化和起源。头骨是特别多样化，由于激烈的自然选择喂养生物力学。我们调查了营养适应的遗传和分子起源马拉维湖慈鲷，经历了一个典型的进化辐射。我们分析了形态差异的横向和腹侧头形状之间的食虫动物，吃吸食，专性咬草食动物，和他们的F2杂种。我们确定了一系列的形态特征的变化，包括下颌骨的宽度，下颌骨的长度和颊的长度，直接影响喂养的运动学和功能。利用数量性状基因座（QTL）定位，我们发现，许多小的影响基因影响这些颅面适应。一些性状的间隔丰富的钾运输和感觉系统相关的基因，后者建议共同进化的摄食结构和觅食的感觉适应。尽管这些迹象的共同进化的结构，形态性状并没有表现出协变。此外，表型在很大程度上映射到不同的遗传间隔，这表明共同的遗传基础不会产生协调的形状变化。总之，这些都表明，颅面特征主要是继承作为单独的模块，这赋予了一个高潜力的形态多样性的演变。虽然这些性状不受遗传多效性的限制，但摄食和感觉结构的功能需求可能会对变异产生限制。总而言之，我们提供了对营养适应的定量遗传基础的见解，确定了影响形态进化方向的机制，并为颅面变异提供了分子进展。
Skull and jaw shape are critical to how an animal eats. The goal of this work was to examine how facial variation evolves and the genetic basis of these changes. We used two species of Lake Malawi cichlids with different facial shapes, one which has evolved to eat prey by suction feeding, a second that bites algae from rocks, as well as hybrid individuals generated by artificial mating of the two species. We found a series of changes in craniofacial structure including the shape of the lower jaw and throat region that impact how animals perform at suction feeding and biting. We then identified genetic regions that regulate these facial shapes. These genetic regions suggested that evolution of the senses, among other traits, may play an important role in facial evolution. Also, evolution of different parts of the face are controlled by distinct genetic regions. Despite this, cichlids that eat similar ways have similar facial shapes, suggesting that the function of jaw movement places certain limits on facial evolution in cichlid fishes. Overall, this work provides insights into how the face evolves, how these changes relate to feeding, and the genes and molecules that regulate craniofacial variation. Since Darwin, biologists have sought to understand the evolution and origins of phenotypic adaptations. The skull is particularly diverse due to intense natural selection on feeding biomechanics. We investigated the genetic and molecular origins of trophic adaptation using Lake Malawi cichlids, which have undergone an exemplary evolutionary radiation. We analyzed morphological differences in the lateral and ventral head shape among an insectivore that eats by suction feeding, an obligate biting herbivore, and their F2 hybrids. We identified variation in a series of morphological traits—including mandible width, mandible length, and buccal length—that directly affect feeding kinematics and function. Using quantitative trait loci (QTL) mapping, we found that many genes of small effects influence these craniofacial adaptations. Intervals for some traits were enriched in genes related to potassium transport and sensory systems, the latter suggesting co-evolution of feeding structures and sensory adaptations for foraging. Despite these indications of co-evolution of structures, morphological traits did not show covariation. Furthermore, phenotypes largely mapped to distinct genetic intervals, suggesting that a common genetic basis does not generate coordinated changes in shape. Together, these suggest that craniofacial traits are mostly inherited as separate modules, which confers a high potential for the evolution of morphological diversity. Though these traits are not restricted by genetic pleiotropy, functional demands of feeding and sensory structures likely introduce constraints on variation. In all, we provide insights into the quantitative genetic basis of trophic adaptation, identify mechanisms that influence the direction of morphological evolution, and provide molecular inroads to craniofacial variation.
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影响因子：
2.9
作者：
ARNOLD, SJ
通讯作者：
ARNOLD, SJ
影响因子：
--
作者：
Atta, K. I.
通讯作者：
Atta, K. I.
DOI：
10.1073/pnas.96.9.5107
发表时间：
1999-04-27
影响因子：
11.1
作者：
Albertson, RC;Markert, JA;Kocher, TD
通讯作者：
Kocher, TD
影响因子：
16.6
作者：
Arbour, Jessica H.;Curtis, Abigail A.;Santana, Sharlene E.
通讯作者：
Santana, Sharlene E.
影响因子：
4.6
作者：
Berndt, Jason D.;Halloran, Mary C.
通讯作者：
Halloran, Mary C.