Variation in opsin genes correlates with signalling ecology in North American fireflies.
Variation in opsin genes correlates with signalling ecology in North American fireflies.
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DOI：
10.1111/mec.13346
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发表时间：
2015-09
影响因子：
4.9
通讯作者：
Hall DW
中科院分区：
文献类型：
--
作者：
Sander SE;Hall DW
信号接收的基因应该进化以最大限度地提高特定环境中的信号检测。在动物中，视蛋白（视觉色素的蛋白质成分）预计会根据这种预期进化。萤火虫以其生物发光的交配信号而闻名。夜间活动物种的眼睛有望最大限度地检测典型低光环境中发出的同种信号颜色。对于在明亮的白天环境中过渡到昼夜活动的物种来说，这是预料之外的。在这里，我们测试了视蛋白基因序列在改变萤火虫眼睛光谱敏感性中发挥作用的假设。我们使用 4 个萤火虫物种的基因组和转录组测序、另外 6 个物种的转录组测序以及其他 28 个物种的靶向基因测序来鉴定北美萤火虫中存在的所有视蛋白基因，并阐明正选择下的氨基酸位点。我们还确定视蛋白中的氨基酸取代是否与信号模式、信号颜色和光环境的进化变化有关。我们在所有萤火虫物种中仅发现两种视蛋白，一种是长波长视蛋白，一种是紫外线视蛋白，并确定了 25 个可能与确定光谱灵敏度有关的候选位点。此外，我们发现在向昼间活动过渡时进化速率升高，并且与光环境变化相关的 LW 视蛋白的选择性限制发生变化。我们的结果表明，眼睛光谱敏感性的变化至少部分是由于视蛋白序列造成的。萤火虫仍然是研究信号、受体和信号环境进化的有前途的系统。
Genes underlying signal reception should evolve to maximize signal detection in a particular environment. In animals, opsins, the protein component of visual pigments, are predicted to evolve according to this expectation. Fireflies are known for their bioluminescent mating signals. The eyes of nocturnal species are expected to maximize detection of conspecific signal colors emitted in the typical low-light environment. This is not expected for species that have transitioned to diurnal activity in bright daytime environments. Here we test the hypothesis that opsin gene sequence plays a role in modifying firefly eye spectral sensitivity. We use genome and transcriptome sequencing in four firefly species, transcriptome sequencing in six additional species, and targeted gene sequencing in 28 other species to identify all opsin genes present in North American fireflies and to elucidate amino acid sites under positive selection. We also determine whether amino acid substitutions in opsins are linked to evolutionary changes in signal mode, signal color, and light environment. We find only two opsins, one long wavelength and one ultraviolet, in all firefly species and identify 25 candidate sites that may be involved in determining spectral sensitivity. In addition, we find elevated rates of evolution at transitions to diurnal activity, and changes in selective constraint on LW opsin associated with changes in light environment. Our results suggest that changes in eye spectral sensitivity are at least partially due to opsin sequence. Fireflies continue to be a promising system in which to investigate the evolution of signals, receptors, and signaling environments.