Detecting associations between genomic changes and phenotypic differences is fundamental to understanding how phenotypes evolved. By systematically screening for parallel amino acid substitutions, we detected known as well as novel cases (Strc, Tecta, and Cabp2) of parallelism between echolocating bats and toothed whales in proteins that could contribute to high-frequency hearing adaptations. Our screen also showed that echolocating mammals exhibit an unusually high number of parallel substitutions in fast-twitch muscle fiber proteins. Both echolocating bats and toothed whales produce an extremely rapid call rate when homing in on their prey, which was shown in bats to be powered by specialized superfast muscles. We show that these genes with parallel substitutions (Casq1, Atp2a1, Myh2, and Myl1) are expressed in the superfast sound-producing muscle of bats. Furthermore, we found that the calcium storage protein calsequestrin 1 of the little brown bat and the bottlenose dolphin functionally converged in its ability to form calcium-sequestering polymers at lower calcium concentrations, which may contribute to rapid calcium transients required for superfast muscle physiology. The proteins that our genomic screen detected could be involved in the convergent evolution of vocalization in echolocating mammals by potentially contributing to both rapid Ca²⁺ transients and increased shortening velocities in superfast muscles.

中文翻译：

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回声定位哺乳动物中快速抽搐的肌肉蛋白中的分子平行性。

检测基因组变化和表型差异之间的关联是了解表型如何进化的基础。通过系统地筛选平行氨基酸取代，我们检测到回声蝙蝠与齿鲸之间蛋白质中平行性的已知以及新颖案例（Strc，Tecta和Cabp2），这可能有助于高频听力适应。我们的屏幕还显示，回声定位的哺乳动物在快速抽搐的肌肉纤维蛋白中表现出异常多的平行取代。回声定位的蝙蝠和带齿的鲸鱼在被捕食时都会产生极高的呼出率，这在蝙蝠中显示是由特殊的超快肌肉提供动力的。我们证明了这些具有平行取代的基因（Casq1，Atp2a1，Myh2和Myl1）在蝙蝠的超快发声肌肉中表达。此外，我们发现小棕蝙蝠的钙存储蛋白calsequestrin 1和宽吻海豚在功能上趋同于在较低钙浓度下形成含钙螯合聚合物的能力，这可能有助于超快肌肉生理快速钙瞬变。我们的基因组筛选检测到的蛋白质可能通过潜在地促进快速的Ca ²⁺瞬变和增加的超快肌肉缩短速度而参与回声定位哺乳动物的发声收敛进化。