Evolution of an adaptive behavior and its sensory receptors promotes eye regression in blind cavefish.
Evolution of an adaptive behavior and its sensory receptors promotes eye regression in blind cavefish.
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适应性行为及其感觉受体的进化促进了盲洞鱼中的眼部回归。
DOI：
10.1186/1741-7007-10-108
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发表时间：
2012-12-27
期刊：
影响因子：
5.4
通讯作者：
Jeffery WR
中科院分区：
文献类型：
--
作者：
Yoshizawa M;Yamamoto Y;O'Quin KE;Jeffery WR
自达尔文时代以来，动物如何以及为什么在适应黑暗和食物有限的洞穴环境的过程中失明一直困扰着生物学家。最近，基于对硬骨鱼Astyanax mexicanus的研究，提出了几种不同的适应性假设来解释眼睛退化，Astyanax mexicanus由失明的穴居鱼（穴居鱼）和有视力的水面鱼（水面鱼）组成。其中一种假设是，通过Sonic Hedgehog （SHH）信号的多效性作用，眼睛退化是对与眼睛发育负相关的建设性性状的间接选择的结果。然而，随后的遗传分析表明，其他机制也有助于Astyanax洞穴鱼的眼睛退化。在这里，我们介绍了一种新的方法，通过研究一套非视觉建设性性状和眼睛退化之间的表型和遗传关系来解决这个问题。通过对表层鱼类、Pachón洞穴鱼种群及其杂交后代的定量遗传分析，我们发现，自适应振动吸引行为（VAB）及其感觉受体，即洞穴鱼眼窝（EO）内的浅表神经鞘（SN），与眼睛尺寸缩小具有遗传相关性。这3个性状的数量性状位点（QTL）在Astyanax连锁群（LG） 2和17上形成2个相同或重叠的QTL集群，而在LG 13上的shh位点不形成QTL集群。洞穴鱼EO - SN的消融证明了这些感觉受体在VAB表达中的重要作用。此外，通过shh过表达诱导表面鱼眼睛退化的实验表明，眼睛缺失不足以促进VAB或EO SN的出现。我们得出结论，增强VAB和EO SN的自然选择通过遗传连锁或遗传多效性之间的拮抗关系间接促进了Pachón洞穴鱼种群的眼睛退化。该研究表明，在洞穴环境的适应性进化过程中，非视觉感觉系统的进化与眼睛退化之间存在权衡关系。
How and why animals lose eyesight during adaptation to the dark and food-limited cave environment has puzzled biologists since the time of Darwin. More recently, several different adaptive hypotheses have been proposed to explain eye degeneration based on studies in the teleost Astyanax mexicanus, which consists of blind cave-dwelling (cavefish) and sighted surface-dwelling (surface fish) forms. One of these hypotheses is that eye regression is the result of indirect selection for constructive characters that are negatively linked to eye development through the pleiotropic effects of Sonic Hedgehog (SHH) signaling. However, subsequent genetic analyses suggested that other mechanisms also contribute to eye regression in Astyanax cavefish. Here, we introduce a new approach to this problem by investigating the phenotypic and genetic relationships between a suite of non-visual constructive traits and eye regression. Using quantitative genetic analysis of crosses between surface fish, the Pachón cavefish population and their hybrid progeny, we show that the adaptive vibration attraction behavior (VAB) and its sensory receptors, superficial neuromasts (SN) specifically found within the cavefish eye orbit (EO), are genetically correlated with reduced eye size. The quantitative trait loci (QTL) for these three traits form two clusters of congruent or overlapping QTL on Astyanax linkage groups (LG) 2 and 17, but not at the shh locus on LG 13. Ablation of EO SN in cavefish demonstrated a major role for these sensory receptors in VAB expression. Furthermore, experimental induction of eye regression in surface fish via shh overexpression showed that the absence of eyes was insufficient to promote the appearance of VAB or EO SN. We conclude that natural selection for the enhancement of VAB and EO SN indirectly promotes eye regression in the Pachón cavefish population through an antagonistic relationship involving genetic linkage or pleiotropy among the genetic factors underlying these traits. This study demonstrates a trade-off between the evolution of a non-visual sensory system and eye regression during the adaptive evolution of Astyanax to the cave environment.
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影响因子：
3.4
作者：
Bradic M;Beerli P;García-de León FJ;Esquivel-Bobadilla S;Borowsky RL
通讯作者：
Borowsky RL
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