Abstract
Circadian rhythms not only influence the overall daily routine of organisms but also directly affect life activities to varying degrees. Circadian locomotor output cycle kaput (Clock), the most critical gene in the circadian rhythm feedback system, plays an important role in the regulation of biological rhythms. Here, we aimed to elucidate the evolutionary history of the clock gene family in a taxonomically diverse set of vertebrates, providing novel insights into the evolution of the clock gene family based on 102 vertebrate genomes. Using genome-wide analysis, we extracted 264 clock sequences. In lobe-finned fishes and some basal non-teleost ray-finned fishes, only two clock isotypes were found (clock1 and clock2). However, the majority of teleosts possess three clock genes (two clock1 genes and one clock2 gene) owing to extra whole-genome duplication. The following syntenic analysis confirmed that clock1a, clock1b, and clock2 are conserved in teleost species. Interestingly, we discovered that osteoglossomorph fishes possess two clock2 genes. Moreover, protein sequence comparisons indicate that CLOCK protein changes among vertebrates were concentrated at the N-terminal and poly Q regions. We also performed a dN/dS analysis, and the results suggest that clock1 and clock2 may show distinct fates for duplicated genes between the lobe-finned and ray-finned fish clades. Collectively, these results provide a genome-wide insight into clock gene evolution in vertebrates.
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We thank members from Peng’s lab for constructive discussion. This work was funded by the grant from the National Natural Science Foundation of China (No. 31872204).
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This work was funded by the grant from the National Natural Science Foundation of China (No. 31872204).
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ZP contributed to the study conception and design. YM, FS, and QZ contributed to material preparation, data collection and analysis. YM prepared the first draft of the manuscript and all authors commented on the manuscript. All authors read and approved the final manuscript.
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Mao, Y., Shao, F., Zhao, Q. et al. Molecular Evolution of clock Genes in Vertebrates. J Mol Evol 89, 494–512 (2021). https://doi.org/10.1007/s00239-021-10020-6
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DOI: https://doi.org/10.1007/s00239-021-10020-6