Mammalia comprises a great diversity of diet types and associated adaptations. An understanding of the genomic mechanisms underlying these adaptations may offer insights for improving human health. Comparative genomic studies of diet that employ taxonomically restricted analyses or simplified diet classifications may suffer reduced power to detect molecular convergence associated with diet evolution. Here, we use a quantitative carnivory score—indicative of the amount of animal protein in the diet—for 80 mammalian species to detect significant correlations between the relative evolutionary rates of genes and changes in diet. We have identified six genes—ACADSB, CLDN16, CPB1, PNLIP, SLC13A2, and SLC14A2—that experienced significant changes in evolutionary constraint alongside changes in carnivory score, becoming less constrained in lineages evolving more herbivorous diets. We further consider the biological functions associated with diet evolution and observe that pathways related to amino acid and lipid metabolism, biological oxidation, and small molecule transport experienced reduced purifying selection as lineages became more herbivorous. Liver and kidney functions show similar patterns of constraint with dietary change. Our results indicate that these functions are important for the consumption of animal matter and become less important with the evolution of increasing herbivory. So, genes expressed in these tissues experience a relaxation of evolutionary constraint in more herbivorous lineages.

中文翻译：

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食草动物分子约束的收敛松弛揭示了肝脏和肾脏功能在哺乳动物饮食中的作用变化


哺乳动物包括多种多样的饮食类型和相关的适应性。了解这些适应背后的基因组机制可能为改善人类健康提供见解。采用分类学限制分析或简化饮食分类的饮食比较基因组研究检测与饮食进化相关的分子趋同的能力可能会降低。在这里，我们对 80 种哺乳动物物种使用定量食肉动物评分（表示饮食中动物蛋白的含量）来检测基因的相对进化率与饮食变化之间的显着相关性。我们已经确定了 6 个基因——ACADSB、CLDN16、CPB1、PNLIP、SLC13A2 和 SLC14A2——它们随着食肉动物评分的变化而经历了进化约束的显着变化，在进化出更多草食性饮食的谱系中变得不那么受限制。我们进一步考虑了与饮食进化相关的生物学功能，并观察到随着谱系变得更加食草，与氨基酸和脂质代谢、生物氧化和小分子运输相关的途径经历了纯化选择减少。肝肾功能随饮食变化表现出相似的约束模式。我们的结果表明，这些功能对于动物物质的消耗很重要，并且随着食草动物的增加而变得不那么重要。因此，在这些组织中表达的基因在更多的草食性谱系中经历了进化限制的放松。