Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo, Oslo, Norway.
Institute of Fisheries Ecology, Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries, Hamburg, Germany.
Sci Rep. 2017 Aug 11;7(1):7956. doi: 10.1038/s41598-017-08286-2.
Understanding the genetic basis of adaptation is one of the main enigmas of evolutionary biology. Among vertebrates, hemoglobin has been well documented as a key trait for adaptation to different environments. Here, we investigate the role of hemoglobins in adaptation to ocean depth in the diverse teleost order Gadiformes, with species distributed at a wide range of depths varying in temperature, hydrostatic pressure and oxygen levels. Using genomic data we characterized the full hemoglobin (Hb) gene repertoire for subset of species within this lineage. We discovered a correlation between expanded numbers of Hb genes and ocean depth, with the highest numbers in species occupying shallower, epipelagic regions. Moreover, we demonstrate that the Hb genes have functionally diverged through diversifying selection. Our results suggest that the more variable environment in shallower water has led to selection for a larger Hb gene repertoire and that Hbs have a key role in adaptive processes in marine environments.
了解适应的遗传基础是进化生物学的主要谜团之一。在脊椎动物中，血红蛋白已被充分证明是适应不同环境的关键特征。在这里，我们研究了血红蛋白在多样化的硬骨鱼目 Gadiformes 中对海洋深度适应的作用，该目物种分布在温度、静水压力和氧气水平差异很大的广泛深度。我们使用基因组数据为该谱系的部分物种特征描述了完整的血红蛋白 (Hb) 基因库。我们发现 Hb 基因数量与海洋深度之间存在相关性，在栖息在较浅、上层水域的物种中数量最高。此外，我们证明 Hb 基因通过多样化选择发生了功能分化。我们的结果表明，较浅水域中变化更大的环境导致了对更大 Hb 基因库的选择，并且 Hbs 在海洋环境中的适应过程中起着关键作用。
